Where I am, I can pay for gigabit duplex or 500Mbps cable. The issue is that the upload speed on the cable circuit is only 30Mbps and I have multiple people streaming from my Plex server, playing games on servers I run, or I might be checking my security cameras while I'm out and about. The only time 300Mbps isn't enough for me is on big files from beefy CDNs like Steam, but 30Mbps gets constraining pretty quick.

they compare Gigabit with 500MBit. That’s not nearly that much of a difference

Not much of a difference in price either in most places. usually it's like 10-20% extra to double the speed.

The main point of the post is to show whether a regular user really benefits from Gigabit, and no, they don’t.

This is true, but to claim there is no point is false, saying that for most 500 Mbit/s is better value would be a way better headline IMO, heck most people will do fine with 100 Mbit/s.
We pay €58 for 1 Gigabit, and I think 500 Mbit is €49 if I recall correctly, so the difference is not a lot.
Of course it also matters if you are just a single person or a family of more people.

PS:
There was a use I forgot to mention, and that is when upgrading my OS, I use a rolling release distro of Linux, and I have quite frequent updates, most are small and finish in a matter of seconds, and even the biggest updates can usually finish within a couple of minutes. This is quite nice too.

Anyways of course lower speeds can be better value depending on the use case, but for us the cost of higher speed is negligible, and it's nice for families not to be slowed down just because someone is using a bit of bandwidth.