The only reason SOTA wants the mat in use is because if the platter is not kept clean,you can get noise on the vinyl,from the vacuum pressure.This is not a problem,if you are good in keeping the platter clean.
As for the sound,I have had multiple Sotas over the years.My pals,also have had quite a few.What can I say.If you don't want to go bare,fine.The sound to ALL of my audio group,and myself is a BIG improvement going bare.
Think about it.The bare platter is SOTA's proprietary material,that supposedly mates with the vinyl to form a massive interface.Why would an intermat protect that interface?It only slightly softens the sound,and does not have the dynamics,and resolving capability of the "CORRECT" interface,which must be bare,for the "vinyl formula" platter top to do it's magic!We have compared,multiple times on a very high res set-up,and there is no contest!Sorry to disagree,but you're off on this one.Best wishes!