You’ll be fine, both in Japan and back home I’ve lent people my card and vice versa, the only time I ever had someone look at the name was buying something from Bic Camera. It was over 5k yen so I wanted to get the tax discount, and they looked at my passport and compared the name on my debit card.

I own the domain firstname.countrycode so my email address is email@firstname.countrycode, haven’t really had many people comment on it though. the previous owner didn’t do anything with it and I thought about buying it from him, but a few years ago he forgot to renew it so I snatched it up

I was in Berlin last month and spent €16.50 for a 50ml bottle