Flash made my Waterfox freeze all the time, so I uninstalled it, anticipating that I’d forego watching online videos. To the contrary, most videos play just fine—I rarely forego one.
Some sites like Netflix still play Flash.
YouTube content is now HTML-5.
There is no good reason to run Flash with its being a resource hog and laden with unfixed vulnerabilities.
Unfortunately, some sites such as ‘soap-opera sirens’ and ‘truckstop tarts’ (not their real names) still require flash to play many of the vids there. :(
*sigh* Some of those are quite interesting. Until they manage to convert, I fear I must at times use Flash to continue to peruse their content. *grin*