getParticlePosition defaults to cell units

[PrometheusPi]

In PIConGPU, we have a new method to get a particle's position:

auto const [xmw_sub_cell_pic,ymw_sub_cell_pic,zmw_sub_cell_pic] = getParticlePosition<DomainOrigin::MOVING_WINDOW, PositionPrecision::SUB_CELL, PositionUnits::PIC>(domainInfo, particle); 

The default for PositionUnits is CELLS, which makes it quite confusing for the unit system of the binning plugin (especially in PICMI).

Is there a more intuitive way to define a default?
(discussed with @ikbuibui offline)