I have no inhibition to using my phone for big purchases, mostly because I have young children and don't have time to sit at a computer after work. Anyway, I thought to myself, what is the most expensive thing that I've purchased on my phone? Millisecond later remembered we bought a minivan last year.
Short story: on the way home from an ultrasound where we found out we were having twins, my wife and I were like "we're going from 1 to 3 kids... Guess we're getting a minivan sooner than we thought we would." We did the whole car search mostly with our phones, my wife used her iPad a bit in the search, and we went to one local dealership, but ended up getting one that shipped from about 1k miles (1.6k kilometers) to us.
Idk if it fully counts as purchasing it on my phone, because I had to whip out a computer to docusign some stuff (maybe I could have done that on my phone too, but I do prefer that kind of work on a computer), but otherwise I applied for a loan from my bank and put in the purchase from my little pocket thing. Overall it was incredibly nerve wracking, but it did turn out to be in good condution and all that. Twins are also in good condition, fwiw.