Sometimes I change devices to try a different code sample on different hardware, or for early POC switch between dev kits and development boards. While it is possible to write down and remember the different chips, since the debugger knows what they are, it is way easier for the debugger to help you switch. Sometimes it can be hard to find the full part number in the dev-kit documentation. This would make it easier to get started with a dev-kit too.
Of course this shouldn't be automatic or anything, it just would be nice to be able to select your device by whatever you have attached at the time.