Is the pendant for PD Converter chargers worth while?

The reason to change modes to higher or lower both have to do with charging off grid. If those reasons don't apply to you, then you don't need the pendant.

1. You want faster charging and need to force 14.4v instead of the 13.6 it only went to by itself.

2. Your small gen can't take the VA draw when at 14.4 so you need to knock it back from 14.4 where it went by itself to 13.6 where now your small gen can handle the load.