I would say it's not a low part count on BoM when I think about it. It's that it utilizes low complexity (i.e. off the shelf) parts that won't be impossible to find or service. That's what I think when I say "low BoM". You have a budget to fit in that BoM. Give someone like JD a BoM budget for Jurassic park home VS JP premium and you learn to get creative with less complex/expensive parts but still make a fun game.
I don't need some $1000 bash toy all the time, sometimes I just want some targets, slings and a drop targets with a plain old scoop that could do the same thing.