On an individual level for simple transactions, then no, there is no difference for you between opt in or full RBF.

The main reasons for full RBF are explained in one of the mailing list posts I linked in the OP: https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-June/019074.html

In short, full RBF eliminates a number of DoS attacks against multi-party transactions such as Lightning channels and coinjoins, therefore allowing further development of these technologies.