If you want the gods honest truth, it is the thing that will hold you back the most and the thing you will need the least. It is a waste of time but it proves to the industry that you can actually sit down and apply yourself. That is all pure and simple.
With respect, I disagree. I was involved with a regional airline recruitment program 2009-2011 and we found ourselves hemmed in a number of times by great FOs who would make great captains except they didn't have their #$%^ exams done when we needed to upgrade them.
Any employer will be looking for the pilot they can upgrade. Once you get into the regional you will rack up hours and for all sorts of reasons the company may need to upgrade you before you, they, or anyone else expected it.