True. But one of the key selling points of LTWOO er9 for me is the flexibility it offers. I wouldn't have to upgrade my drivetrain components. I keep my lightweight 11sp cassette. I keep my chain. I keep my powermeter crankset and I only upgrade to electronic shifting. In my country, the cheapest offer for LTWOO er9 is 460 EUR. Nothing else can match that.
105 Di2 at that kind of discount is tempting, but I'd have to upgrade to 12speed and downgrade some of my drivetrain components.
There's also super cheap offers for Sram Force etap upgrade kits. But again, I'm stuck with 12 speed, I need a different freehub body, different cassette, different chain, different chainrings. So all in all these options are always significantly more expensive.
If you build a bike from scratch and have no other components lying around, I agree that LTWOO is a lot less tempting, however.