I'm scratching my head wondering how you come to this conclusion at all. We're not even talking a single backup point here. We're talking a 2nd backup following a standard 3-2-1 strategy. Cloud storage is statistically far more resilient to issues than any single backup disk strategy you could come up with as a home user.
Statistics include people who can't DIY so I have to assume the cloud storage customers have different liabilities and capabilities. It also doesn't rule out the getting locked out or service suspension, whatever. Mistakes happen. Getting your data back eventually, slowly, isn't as convenient to me as always having a few copies lying around. That was the thought years ago but it has proven to be reliable over actual use all that time.
Like again, you say you're scratching your head at this, but how on earth is basic statistics a head scratcher? A thumb drive more resilient than a cloud? The notion is just honestly absurd. Your what ifs that you base it on are equally absurd.
It's not absurd at all to recognize account lockouts happen, hacks happen, site internet access downtime happens. (particularly if a fire/natural-disaster enough to destroy local backup media).
If you get locked out of your cloud account - You have another backup.
If the service goes under - You migrate your backup set to another service, just like you manage your other backup media.
It gets hacked - They restore from their own backups.
If your flash drive fails, you have another backup too. Remember we're talking about only 60GB, I can literally buy a new flash drive every 2 months at lower cost, and have so many redundant copies that I'm tripping over them, if I felt I needed that many which I don't.
You don't have internet access due to fire / flood / etc. - You likely lost your thumb drive backup as well.
Not at all, as already stated I have one in my pocket right now, on my phone, on my desk, and something that's not sensitive data like music files, I could throw just about anywhere without security issues of someone else happening upon it.
It's pretty preposterous in this scenario to think you have everything you need in this scenario including something to play music on if you only just had your precious thumb drive with music on it, but a stop at your local library or McDonalds parking lot is just a bridge too far.
Your accounts are seized by law enforcement - You have another backup.
Yes, that other backup, and the other, are USB flash thumb drives, because more reliable for this purpose.
The thumb drive isn't "precious", that's kind of the point, a low cost reliable way to keep redundant local copie of data, so low cost that you can have redundancy coming out the wazoo if it worries you that much - it does not worry me, I've been doing this successfully since the first affordable flash drives hit the market, around 20 years ago.
The reality is that thumb drives, SD Cards, etc. are all bargain basement devices with terrible reliability in general. Yes things go wrong in cloud, which is why you pay them to have the resiliency to deal with it.
See above, I haven't lost a single bit of data over ~20 years of USB flash drive use. I have lost a single flash drive at a time, very few times over those decades, but I never advocated having only a single point backup of a single flash drive. Just like a cloud has redundant backups, so should a flash drive user. Does that cloud tell you every time they have a hard drive failure? Of course not, they have redundancy that seems invisible to the end user, but HDD failure is a far more routine thing for a cloud service than USB flash drive failure has been in my use.
Coming to the conclusion that a USB Flash Drive is more resilient than cloud is indeed a head scratcher. You need only look at the MTBF (if they even publish it) to reach the correct conclusion.
MTBF is meaningless for storage devices, mostly tells you infant mortality rate, but even then it is more applicable to cloud storage HDD failure. Besides, doesn't matter, when you have redundant media and it outlasts your required service life. In this music file storage application, it's not getting hammered with writes like cloud HDDs are. Even so, as stated previously I replace them every few years for capacity increase purposes, and it's nice that cost/capacity went up so much over the years too.
Details matter! Someone who can't factor in these details (average home user), is going to be more likely using the cloud service (if they can even figure out how to do that), as is someone with more sensitive data they can't have lying around on a flash drive, or a lot more data where it is cost prohibitive to use that much flash storage. That just isn't the case with 60GB of music.
If you are having failures from redundant USB flash drives to the point where you're losing data, then for whatever reason it isn't the right choice for you.
I suppose we'll both just keep doing what works well for each of us. I never argued that it wasn't better to have BOTH a flash drive AND cloud storage, but forced to pick one or the other for 60GB of music, USB flash drives every time... plus, it's kinda HANDY to have the music on my phone too!