I'm assuming that it's optional because Kobo is probably paid to include that crapware. If they weren't being paid for it, it wouldn't make sense to include it since people could simply download it from the market place. (Presumably it was in the original market placed used by Kobo, and it's almost certainly in Google Play.)

But yeah, I removed that stuff. I didn't benchmark things, but my Vox doesn't seem to get bogged down anymore. For added fun, I removed most of the Google stuff too. The amount of tracking that Google does these days is just plain creepy.