With an option to turn it on or off I see no inherently bad thing with implementing it; just cause YOUR computer can't handle it, it doesn't mean others can't. Really the same argument goes with some complex flames that cause most setups to slow down, /opt gif 0 instead of /opt particles 0 and done.
When it comes to epileptic seizures the same could be argued with an color altering flame going spastic, or multiple coloured flames. So running that as an argument would be the same as arguing against flames as they could case (e) seizures...
Since (most) gifs are 8 bit, and the file seize could be limited I see no problem with animated textures, eg a blinking eye on a 512x512 head texture or similar. Yes it would require a TINY bit of extra performance if you have it running, but so does particles, hairs and shaders.