I just have a little question about using SVG with "modern web site". I was lately told that using SVG isn't really a good idea because they use the CPU (Is It linked to the fact SVG is in fact vector graphic ?), which might be bad on some mobile devices because of the low CPU they could have.
So is that "true" ? Because I'haven't found any good article talking about that.
No it's not true.
Here's an old out of date article by Microsoft. It's out of date because all UAs use GPUs extensively these days (assuming the device has a GPU).
Microsoft has removed the elves workshop test but all UAs we're at several hundred presents per minute by the time they did so.
Having said that you can do lots of powerful stuff with SVG so if you display a graphic with hundreds of animating objects, something's got to process that and that processing must use some battery.