The USB-based experiences were based on a system without TPM. If a booting system sees no USB drive with startup key during startup, Bitlocker will ask you to enter the password, provided a 'Password-protector' exists. If it sees the startup-key, it will simply boot Windows. A USB-drive with LED will allow you to verify if the system if even reading the USB-drive; some USB-ports might not be active pre-boot unless you tweak some bios settings.