Neither do I.
its a restrictive and expensive way of sending stuff, that you can send much more in an email.
It is not that expensive compared to data usage of email. You pay $0.25 per MMS regardless of the size. If you have unlimited text (still availble), it is all covered.
On the other hand, any video attachment to email will cause significant data usage. A 1MB video file will cause you 1.5 to 2MB data because of the attachment encoding. If you are on a limited data plan (unlimited is no longer available for new customers), it eats up your cap quickly.