You won't get any argument on that last point from me. Mostly because I have no horse in the race at all...I didn't get into the X-Men until after she got bodyswapped, so Ninja-Betsy is the default in my mind, but your point is a good one.
I was really just spitballing a potential in-universe explanation.
The meta-textual explanation is probably simply that Clairmont and whoever the artist was at the time thought that it would be cool to make her a ninja, and the psi-blades would be a better visual.