And here is the answer of theymos:
Those fields are actually built a bit deeply into SMF for some reason, so it's not completely trivial to change, but it can be done. Low on my to-do list, though, as hugeblack mentioned.
I agreed with this. If someone have interests to contact someone else, they can easily do it through PMs in the forum. Then, if they have interests to do deeper discussions, they can move to other channels. If the forum adds Discord, Telegram, and other current channels, then what happen next if more comunication platforms launched and become widely used in the future. Forum users will ask places for personal contacts, and profile pages might have 100 rows in total. That's weird.