As a USAF retired guy who did the regionals for a couple years then got a great job I say do both.
Most airlines have a computer scoring system and the points rack up in different ways than you might think.
By going to the regionals you get recent training. Some computer scorings want to see training (new aircraft or upgrade) within the last ?? years.

You get some hours (about 700-900 a year)

You risk a checkride bust. It does happen. Some regionals are better than others in training.

Bum. Try to get Evaluator, Instructor, Safety school. These are point getters on the computer scoring.

Network. The people you bum with are you foot in the door at where you want to go.

My 2 cents.

Good luck. Keep bumming. Networking is the intangible that opens the doors.

It will be tough but worth it.