Composite tracking for person device trackers not working?

Does it only choose one, even if multiple are specified?
I was hoping it would use all of them somehow.

Are you asking about the Composite Device Tracker custom integration or the way the Person entity works?

If you want a sensor that takes multiple other sensors into account with weighting you will likely need to set up a Bayesian binary sensor.

Person entity. As it allows you to specify multiple device trackers I thought it would take them all into account.