And slower. Great for plumbing, not so much a 3" aluminum post with 1/4" walls

But hey, I might be wrong. 30yrs in the trades, but I've never tried cutting down an aluminum post with a pipe cutter

Also if the method varies from person to person, or one person uses a unique method, it's easier to get multiple vandalism charges to stick

These things are a pain to use. Especially the cheap ones require more force than you'd expect and occasionally get stuck. They make a good clean cut but it's so slow and awkward that if you were wanting to do vandalism they're impractical relative to a reciprocating saw or better yet portable band saw.

I also wouldn't underestimate the power of spray paint, even though it's simple to fix it's still expensive when the contract specifics all the maintenance must be done by flock themselves.

Would a straight cut be easier to add a union joint to and thus make the cost of repair slightly lower?

I guess it would depend on priorities