It's probably because Kruw is active on Wasabi Wallet community for many years, while people/group behind 3 other coordinator is newer or less known.
Yes I realise that, but doesn't it invoke trust issues? Isn't it bad from a "decentralisation" perspective? Besides, many people (me included) would prefer to not do coinjoins instead of doing coinjoins where a specific entity could see and
potentially track everything. To be fair, I don't know what these co-ordinators do internally, but I guess they could keep logs etc.