Yes, exactly. Resident keys take up storage space. This article that was updated 5 months ago says that the most recent yubikey can support up to 100 discoverable credentials: https://support.yubico.com/hc/en-us/articles/360013790319-Ho... That might sound like a lot, but given that we want to achieve a migration to passwordless across the internet, you will quickly run out of storage space if every shop on the internet wants a dedicated keypair on your device.

Non-resident keys are so much better, because you won't need to worry about this limitation.