I think it might just be as simple as “we make most of the money off the commercial storefront stuff, but private sellers bring us the visibility and audience that made the commercial side work” sort of thing. I wouldn’t be surprised if we do see some sort of enshittification, “optional” optimisation etc.
But it’s definitely good for me, I’ve paid easily over a grand, probably over 2 in ebay fees over the year, never regretted it as the extra visibility you get’s worth every penny but it’ll be nicer to just not :) Especially since my actual sales have fallen tons in recent years with the cost of living crisis etc, I’ll be putting the fee cut straight into the sale price