>>134944The operative phrase there is 'when asking for edits'. Yes, you can argue that it's bloat when you're just using the screenshot to refer to a moment in the episode, but for editing purposes, you want to eliminate as many artifacts as possible.
JPEG is especially bad for anime screenshots because it disrupts and discolors regions of solid color and smooth gradients, and creates a ton of artifacts around every edge. The filesize of a PNG is higher because it's pixel-perfect. You're trading size for quality, and in this instance, quality is all that matters.