that's a good comparison - i think steemit was designed around the rewards system and also around the coin... while minds was designed as competition for facebook, as a more classical feel-good social network which insists on free speech where facebook censors.
So both minds and steemit attract fleeing youtubers, but for different reasons.
I don't see them as being in direct competition at all, but I also find it hard to imagine that they could work together in more than a superficial way.