I upscale comics content pretty regularly, but it's almost never webcomics, but graphic novel content where I haven't found anything better-quality online. But yeah-- "Waifu2" and others can indeed fail pretty hard depending on your source. I'm still kinda experimenting with all that, and probably need to break out GIMP more often.

I have no problem with people calling out "Beep" for the chronic thing he does, but just in case someone is actually curious about the OP, I wanted to add that yes, it's a real and useful option sometimes when your source is tiny and/or full of graphics artifacts.