This is just my opinion, I am no pro tuner. The manifold vacuum is what talks to the carb more or less and gives a better indication of engine load. With any kind of decent horsepower you are either at very little throttle driving around on the street, or you are wide open.

My car has EFI and it runs "speed density" so it only uses the TPS for accel enrichment. It uses manifold vacuum for an engine load reference and bases fueling off of that.

I bought the TPS setup for a carb when my EFI controller was running the ignition only and not the fuel. I didn't put it on right away and after reading some data logs from the track and street I realized I wouldn't gather much from it.