The ecu uses it as another source to determin engine load iirc...but I highly doubt any changes to the timing/fuel are effected by it as that's the job of the afm, tps, and o2....
Many have removed it and run fine but many have also removed an egr system....personally untill someone can really dig into the ecu and tell us why the ecu reads oil pressure I highly doubt removal of the sender will have any negitive effects.
My opinion is strictly based on ignorance of the ecu oil pressure readings...I have no clue so don't take what I say as "advice"....It makes no sense for an ecu to require an oil pressure reading unless we had a low pressure warning on the dash which we don't.