Basically this person is saying they only use 購入 other than in pre-set economics and school-related terms.
So have any of you seen 購買 used directly to mean 買う, or only really in those pre-set terms?
And is 購入 exactly the same as 買う (other than the typical higher formality for it being a 熟語 word)? Do you often encounter it in conversation or just mostly in writing?
Yesterday at the bank I was doing an international transfer, and I had to explain why I was transferring money back home, and when I said “買った” the bank employee wrote “購入した” (it was attributive in this case, so it had to be in non-polite form".
Other than that, I see it on websites, but yeah, I wouldn’t expect it in a conversation that was at a typical formality level.
I agree with Leebo and what that person above mentioned. I really only hear 購入 in more formal situations like websites confirming if you want to purchase something. 購買 I hear a lot in more casual situations like talking about a new game this person bought.
That’s not what the thing seanblue linked said though. As mentioned above, 購買 is used in conversation when talking about the little store that sells bread in high schools (and in the economics term 購買力), but I don’t think you’d really ever use it outside of that to talk about typical 買い物.
Basically, outside of those two specific areas, the writer never uses 購買, and uses 購入 for just about any type of buying, but of course in casual scenarios it’s probably not necessary to use 購入 and just using 買う is fine.
You’re right, I mixed up the two when reading (ironically). I also probably need to see the words more to better understand the differences, but what the hinative article says sounds right.