As Adobe Flash Player is quite notorious for being so much vulnerable in terms of security issues, it appears that it will be discontinued sometime 2 years later so we still have some time to make use of it.
The only reasons to make use of Adobe Flash Player again is probably Flash games as many of the web video players in video sharing sites like YouTube, Nico Nico Douga, etc. are going towards HTML5 for superior security although the NND video player in HTML5 lacks the foreign comments unless you choose a different region for your account.
Last year, I had a tons of gameplay videos of some of the Flash games released in recent times but the discontinuation of Flash Player is something we shouldn't worry about.