Front trimming doesn't happen much. It's a TT bike that's mostly in 3-4 gears at the back.
Problem with buying the whole shebang is I'll want to upgrade the rest of the bike to justify it having a grand's worth of Di2 installed. Yes, that is a problem, it cuts into my beer money.
The single button tt shifters are nice. Especially if it's a training bike. That you might ride off season with gloves on.
1 X 11 with them would be my choice. They ain't cheap though.
Otherwise. Front shifting might not happen much. But front trimming will. And that's auto on di2