I don't run into this, because I'm more or less retired, but I do have the means, due to other needs (and plain old curiosity). I tend to use Box.com or DropBox a lot, so I'd just send them a share link from one of those. If it's a one-time file, probably DropBox. If I want collaboration, or long term availability, Box.com, because it's easier to share folders and set privileges.
Another words, I wouldn't really depend on my phone's native capability, other than it's ability to connect to a multitude of online services that tend to be platform agnostic.
Even if I had Bluetooth file transfer capability, it would be my last desperate choice. Bluetooth is quite slow and range limited. Fine for small files, but if you had a really big file to transfer, do you really want to have to worry about staying in range until the file finishes transferring? That's not to say I dislike the idea of having Bluetooth file transfer. There are times when it's all you've got. I'm just not missing it as much as I would most other tech. At least not in your scenario.
There is also an app called Bump, which works on both Android and iPhone for sharing files. I don't have it though, since, as I said, I don't really need to do anything that specific.