con is you cant keep fishes that need a hiding place.. i.e some wrasse, gobies, blennies...
IMO i dont think it is a need to have LR to house your beneficial bacteria and neither does it become uncycled. i'm sure you have your sump with bioballs/ ceramic rings/ biological filter that houses the necessary bacteria.
Bro Kenyee, AEFW = Acropora Eating Flatworms.. &^#@%!^# pests among SPS