They're good, but I wouldn't say "that good". They cost way more than they should though.

Gaming chairs are basically impersonating race car seats, which are designed to be safe and keep you inside them at high speeds. They are not designed to be comfortable or ergonomic. Companies have started adding weird pads to them to make them seem more legit, but they are still not ergonomic or good for long term sitting.

Office chairs in the other hand, are usually made to be sat in comfortably and properly for long periods of time.

I recommend finding "Herman-Miller-like" chairs, or finding cheap Herman-Millers being sold used etc. I highly recommend mesh backs and bases, as they are way more comfortable than any amount of padding, and they are often pretty ergonomic. They're also way more breathable than a foam pad.

Look at a side view of a spine/skeleton and note that it's curvy and s shaped - you don't want to press that up against flat boards for long periods of time.

Herman-Miller chairs are good, but they're not $1000+ good. You can find plenty of equivalent or better stuff in the $300-$500 range if you just poke around for decent office chairs.

I think they are overrated. I have worked in offices with them and with other chairs and couldn't tell a difference.

No.

What is good are fully supported recliners.

They're just currently out of fashion.