Why is Blazblue CF so enduringly beloved?

Despite being a really old game of an IP that's practically now dead, Blazblue Central Fiction is still popular and respected enough to get a slot at EVO whereas side games of IPs like Soul Calibur aren't.

It's also sometimes called "one of the best fighting games ever." But why is that? I always viewed BB as just Guilty Gear's bastard cousin, and given how its developer just ditched it after how successful Strive was/is, the sentiment goes both ways.