In what way is EGS better as a store? I'll wait.
Steam has a toxic loli pedophile community that they did nothing to curb for years until their hand was forced by EU regulations last year.
Steam had active money laundering schemes taking place on their platform they did nothing to curb until authorities got involved.
They did nothing because these were lucrative revenue streams.
It's easier to find games you're looking for on EGS because it's not filled with shovelware.
EGS has better regional pricing options.
EGS is curated, like Steam used to be when it was better.
Valve hasn't had to have a real marketing strategy in years because they've had a De Facto monopoly of the PC gaming industry. I see a lot of people make the claim that Steam codes being sold on other stores make no money for Steam, but that's not true. Sure, there's no money on the front end, but all that does is trap developers and consumers in their ecosystem. Those other storefronts could never challenge them because without Steam, they'd dry up. Plus, every single Steam code sold requires the consumer to activate it on steam. That means every one of those customers must also download the Steam App, which has the Steam Store... So, it's all advertisement for Steam, even when a competitor is used.
Also, it's not a good look to assume that everyone who doesn't hate the EGS is a shill or a fanboy. I still use Steam, and I only occasionally use EGS. But when I have used it it's been a pleasant experience.
This is the very first time anyone has really tried to directly compete with them on the PC. Sure, there's Origin and Uplay, but those are primarily 1st party vehicles for their respective publishers. GOG exists, but CDPR have never stood up and actively tried to compete because they don't have the revenue to try. They'd get crushed by Valve if they considered them a threat. Remember that Valve went so far as to make their own linux distro and tried to talk gamers into changing operating systems because Microsoft launched their own game store.
To close, the exclusivity deals don't hurt the end user at all. They aren't like console exclusives where the customer is required to buy all new hardware if they want to play the game. Depending on your region, EGS could even offer better pricing(or the option to play the game at all.)