I think Twilio requires its customers to go through the process of registering with the CTIA before allowing use of the SMS API. I abandoned a project because the process was too burdensome. Political campaigns are exempt though.
(Which, as an end-user, I'm happy about...)
I think it's different if you're applying for a shortcode vs a regular or toll free number though. There are different regulations governing all of those.
Having been on the purchasing end for wholesale marketing SMS I can tell you most of sales people will suggest the 'correct' way and happily sell things that let you do it the 'wrong' way.
The only phone number I ever texted was my real cell number, it's no longer worth having a Twilio number for a hobby project.