Really? I mean, no one is going to argue that kanji numbers are more common, but kanji numbers are definitely normal to see. Even beyond things like 二人, 三人 or whatnot, there are plenty of things like 一石二鳥, 百点満点, where it’s normal to see the kanji numbers.
I agree that you’re often not going to see longer numbers written out fully in kanji, but I’ve seen that as well.
Here’s an image from an article explaining how to write the address on a New Year’s card, though you could write it like this on anything, and it uses kanji for the numerals within the address (section 2, and other places on the card as well). It’s fine to write arabic numbers in addresses as well, but this is not unusual.
Though you’ll notice that in this case, they use 一〇 instead of 十 for an address.