To be fair, I fly about 30 times per year, and in the last ten years, I've found that the in-flight wifi actually worked approximately once.
Reasons not to use in-flight wifi:
* It might be broken, but the credit card processing for some reason works fine.
* If you are on a short haul flight, it's going to be disconnected for takeoff/landing so you will get a solid 30m
* If you are on an international flight, it often stops work once you are over the ocean.
I worked on inflight wifi for Qantas, where they share the highest trafficked route in the world - the 60 minute light between Sydney and Melbourne. It was a huge win for the project when we got clearance to enable wifi on the ground for takeoff.
This article from 2017 confirms that it was 15 Mbps at one time: https://www.latimes.com/business/la-fi-travel-briefcase-airl...
It looks like they have since reduced the free tier to less than 1 Mbps and added a paid option that allows you to stream video.
On the return flight it just didn't even work. Fortunately, I'd had newpipe download some content before we left.