DP alt tabbing is faster? Why is that?

Something to do with HDMI handshake between monitor or tv and pc being slower. On my G1 it's a few seconds, while on my old ultrawide who used DP it was almost instant. Not a big deal, but could be an issue for some.

The chill ABL is the only real feature that stood out to me, but I don't keep my monitors too bright so I generally don't run into the fluctuations very much anyway.

Yeah it depends on use case. Some people are more sensitive to that, some don't care. It's a nice thing overall.

Heatsinks are always nice, but already present in a lot of these. The reason so many of them are so thick I guess while my TV is like 4mm thick.

I imagine every bit helps, but that's not something you can actually test reliably. Maybe down the years there will be some data, but yeah.