Both. Nifty-ness feels somehow fun, or rather enjoyable to watch. Functionally this solves a very small but ever-present issue with using vim; perhaps most importantly, the animation is sufficiently fast to be actually unobtrusive, a very rare feat for most such UX changes, and absolutely vital to it's potential to be useful.

It is perhaps the single most impressive text editing visual design change I've ever seen (maybe second to kakoune's verb-noun reordering allowing selection-before-editing visualization). But while most such changes are functional but dull (eg sublime multiline editting), I can confidently say I like looking at this thing go (and the utility is minor, but obvious and good)...