Winning does count for something. That's how your guild gets Crowns, and the amount of Crowns won directly determines how many Merits get handed out. So if your guild doesn't win many matches, it won't get many Crowns, and you yourself won't get many Merits.

We decided each guild member should get the same amount of Merits because that's the only real fair way to distribute them, given that members are likely to have a different number of battles if some guilds don't fill all Frays.

If a participant does not actually submit teams for their matches (i.e. they don't really participate), they won't get any Merits.