WIF support is coming next (ie the OPENDIME private key)
For me the main use case was being able to transfer funds from older seed and/or other devices without exposing them. So loading these seeds as temp on mine and export electrum file for sweeping them. There is no limit on how many temporary seeds you can load, it's just one at a time. Once you reboot they clear and revert back to your stored seed.
Maybe you are confusing these with BIP85 seeds (deterministic seeds)