Of course he is. I do this all the time. You don't actually understand competing products unless you _ACTUALLY_USE_THEM_. I don't mean for 5 minutes in a store. Or, if it's your job, in a controlled office setting. Real life usage is just different, no matter how you look at it - so you don't truly understand the competition, what you're lacking, or what you do better, unless you truly use their products for a period of time.
Don't like the example of competing platforms? Fine - how about testing within a stack? For example - I write apps. I do performance testing when I'm developing so that I think things are fast on low-end devices. But, as anyone who has used a low end device knows, actually using those devices day to day is different than in a controlled environment. You'll have random hiccups, cases where your memory is full due to multitasking or something going on in the OS where everything just slows down. So unless you actually put your SIM card in one of those low end phones and walk around with it for some time, you don't actually understand what that usage is like.
If his job is to be intricately involved in the day to day development of Windows Phone, you have to assume he's using it - on multiple Windows phone devices - every day, all day. Which doesn't leave a lot of time for this sort of competitive analysis. Now that he has a temporary break from those day to day responsibilities he can actually focus on the competition. That's what I would expect a company executive *should* do, there's nothing wrong with it, and it's certainly not a vote of confidence / lack of confidence in his product.
Can we move on? This isn't rocket science.