I don't like or trust Flash very much, but it does work pretty well on Linux these days.
I'm on Gentoo, and technically I could view this in Firefox, so I suppose it works. However, I'm in Chrome at the moment, and in a recent version of Chrome they decided to drop NPAPI support, so plugins (including Flash) no longer function. Technically, they replaced the NPAPI Flash with Pepper Flash (Pepper being a new plugin API, I think); when I upgraded to the version of Chrome that did all this, it was still masked in Gentoo, so it wouldn't install without me specifically unmasking it… which I didn't. This could just be my distro, of course, though Gentoo is quite wonderful for other reasons. It does appear they've unmasked it, so whenever I next upgrade, I can get it.
Even on non-Gentoo, I still feel like there are some hoops to jump through to get it. Distros typically can't offer it in their package repos, due to the license, right? (It's the same with proprietary music/video codecs last I checked.)
Point being, it requires work just to make it work. HTML doesn't require that. It has made me use Firefox more recently, however.