So I just installed the launcher and surprisingly it's not completely horrible from the start. Unlike the previous Social Club launcher it at least managed to log me in properly.
But to me the impressive part was that because my GTA V installation was not working because I have reinstalled Windows 10 after upgrading my PC, Rockstar launcher was able to detect the existing files when I tried to install the game in the same folder from the launcher. So instead of redownloading 86 GB it just downloaded the updates. It also detected Max Payne 3 which I have bought as a physical copy and will allow me to download it digitally.
Did we need another launcher? Hell no, but at least it is not as big of a shitshow as some. The GTA SA offer is pretty lame though. Even if it's one of the more popular GTAs, it can be bought used for next to nothing. At least they could have thrown in GTA IV as well. Interestingly GTA IV is absent from the store altogether. The only purchaseable games are GTA V, GTA SA, GTA VC, LA Noire, MP3 and Bully.
When they release the inevitable RDR2 on PC, I'll have to figure out if I can purchase it for less from another region over VPN so I can feel that I have at least some way fucked R* for doing this double dip thing on their games.