You’re missing the bigger picture. Yes, developers really appreciate that their games work seamlessly on the Steam Deck and Linux with no effort on their part. But there are a couple of knock on effects.

One is that developers now a specific hardware + software combo to test their games with. Even if it’s the same build they’re sending out, they’re still testing their game on the Deck and fixing issues, leading to a better (but not perfect) experience for Linux gamers. Here’s a video of Swen Vincke, CEO of Larian studios playing a game released by his studio on the Steam Deck - https://youtu.be/kzfEkSGa45k. He’s very pleased and promises to test future games released by his studio on the Deck. And he stuck to that promise - Larian released several fixes specifically for the Steam Deck to make Baldur’s Gate III run better. Linux gamers benefit from that.

Second, this increases the % of gamers using Linux. After the Deck’s success in the last couple of years Linux is at 1.91% of the respondents of the Steam Hardware Survey for Nov 2023. Linux was at 1.15% 18 months ago. Doesn’t sound impressive, but if that growth continues and it reaches 3-4%, at that point developers will find shipping native Linux builds more attractive.