It's confusing for students and parents when notification texts come in from several different phone numbers. If all SMS messages from a given school came in from one number, then end users could create that as a contact on their devices so they know who it's from.
This is important because our users report that spam messages come before and after Blackbaud messages, leading some users to believe Blackbaud has been hacked or has given out their phone number. Also some users wish to block or filter messages from unknown senders leading important messages from our school to be blocked.
This also makes it easier to glance through past text messages.