I've only tried it few times via their official docker image; it's reasonably fast (a minute of asciicast took about a minute to convert), but PhantomJS/ImageMa

I've only tried it few times via their official docker image; it's reasonably fast (a minute of asciicast took about a minute to convert), but PhantomJS/ImageMagick do put some load on the CPU while it's generating/combining frames. I never had any problems when I need to make a GIF, but the conversion process does indeed seems very wasteful.