Sun Country Charging for Pre-Assigning Seats

I noticed today that every seat on my Sun Country flight is a “premium” seat worthy of an $8 charge if I check-in online and pick a seat at that time. (Yes, even middle seats where the seats on both sites are occupied.) However, if I go to the airport and check-in in person, there is no charge.

Paying $8 to assure that I’ll have my favorite seat on the plane doesn’t seem too painful, but I’m trying to understand how this benefits Sun Country. If I go to the airport, I’ll likely end up interacting with Sun Country staff rather than serving myself online. Surely, that costs Sun Country money, so what’s less convenient for me is also more costly for them.

It doesn’t seem like our interests are aligned here. Wouldn’t it benefit Sun Country to steer people toward being as self-serve as possible rather than creating incentives to consume front-line staff time assigning a seat to me?

For example, I have received bonus miles from other airlines for checking in online, from kiosks, or using QR code boarding passes. It’s an effective way to get people to try new, more efficient, check-in systems.

Perhaps Sun Country has determined that enough people are willing to cough up $8 to guarantee the seat of their choice? Are they ahead of the curve here? I hope not.