Pirate IPTV is generally awful at best. Good streaming (Netflix, Amazon Prime, Disney) is decent given an average BB connection. I would go as far as to say that in a lot of cases, it's better than satellite as these services are not trying to cram a bazillion channels into a single transponder at RealMedia quality. I certainly find Disney+ streamed in HD quality to be much more pleasant to watch than the same program recorded from BBC over Christmas. Don't forget that many services also offer HDR, which is subtle but gives more colour depth to your image.
However, on the whole I prefer the solidity and predictability of satellite TV.
Can't comment on Sky Glass but given the flaming reviews from literally everyone, I'd say it's crap. And bundling TV into the package is just a marketing gimmick to offload that ancient unit from yesteryear at inflated prices.