@doctormo @georgetakei fairly bad, but it works just fine. Plus it can be compressed back down in storage.
As far as I'm aware, the real reason your mail client or recipient server will reject files over a certain size really has to do with preventing users from completely overflowing messaging servers with shared files either from well-intentioned or malicious users.
If you have your own mail server with tons of storage, you can configure it to save and relay attachments of any size.