Because it doesn’t seem to matter currently if you play ranked games or casual games, the general experience tends to be the same. But one has numbers and things to go with it. You still get people playing to win in casual games and you get people dicking around having fun in ranked games, and the ranks don’t necessarily indicate how they play as a team and a whole bunch of other things that make it less than ideal.
I’m not sure if you’re asking for a name change or a change of balancing/rules/mechanics, etc. surrounding ranked and casual matches… if it’s the latter i agree.