Well, OK, I'd use another laptop that's not mine to watch F1 livestream every once in a while. 😜 But if it's a paid service, I'll forward to them the message. It's happening. Others have already started to demand it as well. (search "flash is obsolete", or "occupyflash" and you'll see it)
I've experienced having a machine without flash since at least nine months and it's already very doable. Youtube and others, I've experienced not a single problem due to HTML5. Regarding CPU use, well, I can't/won't comment further on that, but Flash have been some of the worst memory hogs along with some adblockers in my experience (I use Opera now btw, it's always smooth & responsive unlike Firefox, even if the latter's already a "64-bit" build; and I think it's quite a bit lighter/meaner than Chrome as well).
Casual games are fine, I play pool all the time on my cell and tablet, (but they don't NEED to be made with Flash!), and I think the only recent desktop game built on Flash I played was Machinarium. Hm, there has to be a Flash alternative/wrapper or something that's not so tightly integrated.
I took a quick look at some of the Flash update KBs (they're usually mixed together along with other security updates which require reboot anyway), and especially if some of the files are being used, then yes, you'll still have to restart. Of course you can delay for a couple days maybe. These Flash-related files are basically treated like system files, you'll have to take ownership to remove/modify them (which is why I suggested Unlocker if you're doing it manually).
Now daily built-in AV/antimalware definition/database updates don't require restart, and after a period of manually checking and accepting updates, I decided to put them on _automatic_ BUT also to never have my system restart unless I do it myself. Much more convenient that way. Trust me, I've been and am still seeing a LOT less updates annoyance compared to a machine with Flash still installed. 😀
"Any sufficiently advanced technology is indistinguishable from magic."—Arthur C. Clarke
"No way. Installing the drivers on these things always gives me a headache."—Guybrush Threepwood (on cutting-edge voodoo technology)