Because they are the only regionals offering flow as the chart says. "AAG Wholly Owneds with flow". And I also thought it was interesting that the compensation between the 3 is pretty much the same. So I bracketed them.

I don't know of any other regionals offering flow. Are there any?

I'm not a huge fan of flow, but it's nice to have in your back pocket if all else fails. I would pick a regional based on base (can you drive to work), commutability (if you have to commute), and compensation.

Flow is a recruiting and retention tool in an environment where companies are competing for pilots. It is a way for companies to get you into their airline and then keep you there waiting for the flow. If the regional of your choice happens to offer a flow, that’s great. It’s a good back-up plan if all else fails. But I wouldn't let that be a deciding factor of which regional to join. That's just my opinion, though. For some people flow might be a great option. For instance, if you don't have a degree.