What are you doing with all that phone stuff?

Nothing, I don't have any.

I thought we’re using the internet these days instead of calling that much.

A lot of cheap eSIMs are actually data-only, i.e.: you don't get a phone number.

Or do you just travel much and need the data plans for different countries/continents?

No, not at all. I just get interested in random crap, and now it's SIM cards it seems. Either way, some of these manage to be cheaper than many local offers, or even completely free as I mentioned.

Another thing is some countries, unlike mine, don't require ID verification. So no scanning of your ID card, scanning your face, or perhaps physically sending signed documents via mail and waiting 3 - 5 business days to get your SIM card activated like I had to do with my carrier. e-mail should be enough. This way, phone numbers can be as disposable as e-mail addresses which is just awesome when using some untrusted services that want your phone number.

Lastly, coverage. I already purchased T-Mobile physical SIM from Czech Republic (and yay it works). T-Mobile seems to try to get as many roaming partners as possible in every country. In mine, that's 3 out of 4, and 4th one is my main carrier. So I can connect to every carrier in my country with these 2 SIMs. I just find that pretty cool.
I told you, I get interested by random crap.

Next on my list is GiffGaff (United Kingdom) which I can get for free shipped anywhere in Europe and can also be activated from abroad (as far as I can tell) like that T-Mobile card.