It’s not just a launcher, it’s a storefront. Uplay, EA-whatever, and Rockstar Launcher are all storefronts where you can buy the games those companies make.
The launcher itself is a UI which lets you “launch” the game. Steam for example, is a launcher and a storefront, as is Uplay.
Having all your games in a single launcher/storefront is bad, as it gives a single company entire control over your games, and monopoly pricing.
Also remember that Steam takes a 30% cut, which is totally unnecessary, and is what directly caused giants like Ubisoft and Rockstar to make their own storefronts. Because why pay a 30% tax just for selling your game, this ain’t the 1990s anymore with CD-ROM pressings.
Fuck Steam and it’s monopolistic, 30% rent seeking bollocks.