I travel a lot, and spend time in a lot of random places, stay with friends and such like. My job means that I can set my own schedule most of the time, but sometimes I need to respond to something pretty urgently. So, there's been plenty of times when I've been travelling light and suddenly been asked to pull a bunch of data from a spreadsheet and write some quick report on it, so usually I just ask whoever I'm with if I can use their pc for an hour and get it out the way.
It's certainly possible do it all on a phone, but it's much quicker and more pleasant to just use a proper keyboard and screen. And there have been times (like after a ill-advised encounter with a fountain in Rome) when my phone is temporarily out of action, so if I need to deal with travel arrangements on a public computer it might involve accessing my emails.
I married my partner, after being with them for over a decade, and a few years of living together full-time. It was mostly for admin reasons (we just bought our home, and being married made things easier if one of us died). If it wasn't for that I don't think we would have bothered. We know we love each other, and had decided a few years before that if we'd get married if we ever needed to, so it wasn't like we ever 'proposed'. Just a tiny ceremony with two friends as witness, and we went out to a restaurant for lunch afterwards. I don't think it cost us anything beyond lunch? Maybe a tiny admin fee?
But... I'm so happy we did! It's weird! I never really cared, and rationally, I still think it hasn't changed anything. But somehow it feels... really nice? I still regularly think (and tell them) "I'm so glad I married you". I'm sure there are lots of other things that you can do to symbolise your relationship or commitment. If I got a tattoo inspired by my partner I'd probably have the same feeling of looking at it and thinking of them that I do when I play with my wedding ring (2€ piece of silly junk from aliexpress. And we each bought a bunch of spares so that when we inevitably lose them it's not a problem). But actually a marriage is one of the simplest and cheaper ways (if you don't choose or feel pressured into turning it into a stupid moneysink).
Tldr: didn't care about marriage, got married for tax, and weirdly found it deeply satisfying in a completely unexpected way.