If you oook at the people on youtube printing models, none of thm start the print at the build plate, they all use supports to raise the model off the bed.

I can't think of any other reason except to avoid this outline around the first layers.

I have to say, I' really disillusioned at just how awkward printing a clean first layer is on a resin machine.

Looking into alternative print surfaces at the moment.
Ideally something that doesn't reflect uv light as efficiently as aluminium does.

I've got a project in the works which would definitely benefit from resin printing (making trackballs), just need to get the machine working and sort out a procedure for dealing with uncured resin that you can't put back into the bottle.

Or I might just go with fdm and some sanding lol