A magnetic escutcheon is a security escutcheon that covers the cylinder entrance completely. To open, you first hold a magnetic key to it, the cover slides aside and the keyhole is free for your usual key.
From outside not even the keyhole can be seen, so there is nowhere to start manipulating the cylinder. As well as the protection against force that any escutcheon gives, it stops anyone working on the lock.
It has another advantage that is welcome on the coast: with the cylinder covered, it is protected from dust, sand and salt. That is why it suits homes left empty for spells and exposed doors very well.
You just have to get used to carrying the magnetic key with the others. It is all in escutcheon installation.