FWIW, I went to the extreme of being completely surrounded with Raal Tweets on the bed layer. I also built the Rig primarily for Multi-channel Audio. And I engage in critical listening.
But there is a key balance to whether a person can tell if their system is sounding off or not, beyond knowing the Speakers are not the same brand or model, etc.
Truly I think it is important to do up front but also recognize the flip side that in some ways it might not matter.
*shrugs
Realistically, this is once again what I would refer to as a Personal Values decision.
If one is creating a budget and planning a purchase, Absolutely should they plan to get matching Speakers as much as possibly.
If somebody has multiple Speakers and is perhaps cobbling together an HT Rig from different gear and doesn't mind it... Is that "Wrong?"