Yes, it's a first-party exclusive and yes, it's going to sell a lot of Xbox Series consoles, but Microsoft's policy of delivering PC versions of its tentpole titles opens up Halo Infinite to massive range of gaming hardware. I'd characterise the quality of the PC conversion as variable: the game itself is brilliant and it is possible to have a great experience without owning an Xbox console.
That said, it's also fair to say that the PC version can be unexpectedly heavy on both CPU and GPU, there are many technical blemishes that need addressing, while 343 Studios fails to tap into any of next-gen features that work so well on modern PC set-ups - so there's no ray tracing (yet), no AI-based super-sampling and even variable rate shading (VRS) as seen on the console builds is totally absent on PC. What we have here is fine, but not exactly special and definitely needs a lot of work.