Depends what you want to create I guess. Didn't Google show a 10x performance improvement for a 2D demo when done in WebGL compared to when it's done in canvas a Google I/O or two ago?
Plus, what do you mean by "most browsers"? Are you referring to IE? That's only included in IE9 and IE10, which is like what - 10% of the browser market? You can't include IE6-IE8 in that. So you're only getting about 10% extra market when you're thinking about creating a 2D web game as opposed to a WebGL game, but you lose a 10x performance improvement.
As for mobile browsers - do 2D web games get good performance on mobile? Is anyone even thinking about playing 2D web games on their mobile devices? I assume that even if they work okay, that's still only in the "high-end/latest" mobile devices, which is just a part of the whole smartphone/tablet market.
EDIT: Found it. They show the Microsoft fish demo at 1000 fish with canvas 2D, and then a WebGL version of it with 10,000 fish:
I was really thinking about mobile in terms of hw acceleration and risks/benefits. See comments below.
Don't disagree that WebGL is faster at times, and more useful, just still a bit immature. And I started working on it about 2 years ago so I know WebGL has matured greatly in a short period of time, but until it reaches a mobile browser I still see it as a bit too early.
Then again you could take those same shaders from a WebGL program and port the game/logic to iOS and so that may be an inherent benefit I am missing out on.
Plus, what do you mean by "most browsers"? Are you referring to IE? That's only included in IE9 and IE10, which is like what - 10% of the browser market? You can't include IE6-IE8 in that. So you're only getting about 10% extra market when you're thinking about creating a 2D web game as opposed to a WebGL game, but you lose a 10x performance improvement.
As for mobile browsers - do 2D web games get good performance on mobile? Is anyone even thinking about playing 2D web games on their mobile devices? I assume that even if they work okay, that's still only in the "high-end/latest" mobile devices, which is just a part of the whole smartphone/tablet market.
EDIT: Found it. They show the Microsoft fish demo at 1000 fish with canvas 2D, and then a WebGL version of it with 10,000 fish:
http://youtu.be/MiYND_zvIc0?t=14m3s