Twilight Bag Drop

We are off to the Caribbean from LGW in a couple of weeks and have upgraded from our usual PE to upper class for the first time
We normally check in online and stay at Gatwick the preceding night to avoid the M25 at 8am, dropping the cases into the twilight bag drop when we arrive.
Question is what will we miss by not using the UC check in ..... apart from the obvious which does not bother me ..

We normally check in online and stay at Gatwick the preceding night to avoid the M25 at 8am, dropping the cases into the twilight bag drop when we arrive.
Question is what will we miss by not using the UC check in ..... apart from the obvious which does not bother me ..