performance is still a big issue on mobile devices (I have worked on several commercial html5 games made for firefox-os, but they also work on ios and android,

performance is still a big issue on mobile devices (I have worked on several commercial html5 games made for firefox-os, but they also work on ios and android, where you'd also have native options). There is a huge - HUGE - performance difference factor and while that doesn't matter for every app it matters quite often for games (even simple 2d games in the style of angry-birds). html5 on the desktop on the other hand is plenty fast.