I love minimates because almost every licence produced, is something I like now or have grown up with.
Also... they are toys. I get the same kick out of collecting toys now, that I got as a kid.
It's not necessarily the owning that I like, which is why I currently have few on display, it's the collecting!
Owning or displaying, while nice, is secondary to the collecting - or to paraphrase, it's not the having, it's the getting.
Finding a figure you want in a toy store... getting that package in the mail... ripping it open to get the figure inside... checking out the accessories... getting a whiff of that new toy smell? That's pretty sublime!
2" figures costing under $10 a pack, allow me to regularly get my kicks, without bankrupting myself or filling room after room with toys.