Depends on how you value them and what your goals are. There is the absolute cost which can be huge. I took a trip for 140,000 miles that United wanted $12k for paid tickets. Now would I have paid $12k to go to Australia in business class? No. Would I have considered paying $3-4k? Yes. Would other people pay $3-4k for business when they can get economy for $1100-$1500? No. So the value of those points is different for different people in that one scenario.
To be honest unless you're supplementing your points earning with sign up bonuses or have a huge annual spend you're not likely to get much more than the occasional domestic economy ticket out it it.
The Venture X card is a very strong entry into the premium card market from Capital One. It's got some quirks but with some thought it can be very valuable. The signup bonus at launch was 100k points plus a $200 AirBnB\VRBO credit in addition to their $300 travel credit, 10k bonus miles on anniversary and 2 miles\$ everywhere. It gives a normal Priority Pass membership (aka not the hobbled Amex Plat version) with 2 free guests. Best of all, for groups or families, Authorized Users are free and they can also get 2 free guests. I already signed my wife up so we can guest our two friends in for our Alaska trip free of charge.
So those quirks - they don't have any 'traditional' US based carriers like AA or United. But they do have their partners like Star Alliance members Aeroplan, Turkish, LifeMiles. Aeroplan has a lot of partners outside of Star Alliance so it tends to give more award options than United can and award prices are a bit of a wash - sometimes they are a little more expensive sometimes less. You lose the excursionist perk option but gain the ability to add a stop-over for 5,000 points (except for the US and Canada). Soptovers can be on one ways so you lose the upside of the Excursionist Perk, which requires a round trip, but gain a ton of flexibility (Chase is also an Aeroplan transfer partner). Turkish airlines has 7.5k mile economy award redemptions on United domestic US flights including to Hawaii and Alaska. Business is 12.5k if you can find them. LifeMiles also has the 7.5k domestic US economy awards (although I think they might price Hawaii differently?) LifeMiles charges no fuel surcharges and has some really unique quirks like mixed cabin First Class awards becoming surprisingly cheap. They have Etihad for One World (Iberia, Quantas and BA Avios are there too) which charges 50k miles to Europe from the US compared to 57500 for AA