The only thing I like less than getting a 50-megabyte attachment in an email is not getting it because it bounced. That should happen less frequently now that Google has raised the bar for Gmail accounts, and anything up to 50 megs is A-OK.
Honestly, no one should consider this justification for sending huge attachments all the time — anyway, you still can’t send anything over 25 megabytes — but sometimes email is just the simplest or only way to get something from here to there, and no one wants to see the dreaded “subsystem error” or whatever comes back when you send something too big.
Seriously though, just use a dedicated file sharing service if at all possible. Email is great, but this isn’t what it’s for.