Part 1/6>Gifs are compatible with way more shit
This is somewhat true, and really the only reason GIFs remain alive to this day.
GIFs are compatible with practically all (graphical) web browsers.
WebMs on the other hand still aren't supported by some non-major browsers:http://caniuse.com/#feat=webm
Supported: Firefox, Chrome, Opera, Firefox (Android), Chrome (Android), UC Browser (Android), QQ Browser, Baidu Browser
Somewhat Supported: Edge, Opera Mobile, Android Browser, Samsung Internet
Not Supported: IE, IE Mobile, Safari, iOS Safari, Opera Mini, Blackberry Browser
Though if you're seriously using IE or Safari, you've got bigger problems with feature support.>are way less likely to crash and stop working
This isn't true for major web browsers that support WebM (read: Firefox and Chrome/Chromium).
It was more the case back when in-browser VP8 codecs/players were still being implemented, they're stable now. >automatically loop
WebM support is good enough with Firefox and Chrome/Chromium that you can just right click and check/uncheck "Loop" if you want to enable/disable looping.
Looping for GIFs, on the other hand, is controlled by the image itself in the loopcount parameter. So to enable/disable looping for a GIF, you have to reencode it to change the loopcount parameter.
The ONLY downside of WebMs looping-wise is that for servers to set default looping behavior, they have to use the HTML <video> tag. So if you just browse a .webm URL, the video won't by default loop (right-clicking still works to enable/disable though). For .gif URLs, the browser will honor whatever setting is encoded in the image file.
The gist is that .gif URLs can loop by default, while .webm URLs cannot. Again, this isn't an issue for HTML URLs with embedded WebM files, e.g. 4chan threads, because those have <video> tags; it's only .webm URLs that have this issue.