On the flip side, they are tamper resistant. It would be incredibly difficult for someone to tamper with a Surface tablet siting in a hotel room without leaving marks. This is probably good for travel with a corporate device.
Also, this is not for my threat model, but it could be appropriate for certain corporate travelers or journalists.
BitLocker only allows you ten attempts to enter the TPM PIN, and if the bootloader is modified by an attacker, the TPM will refuse to release the key.
TIL
Also does it require it when comes from hibernation? Because by default Surface Pro powers off after certain time in connected standby, therefore if BitLocker pin is active after wake up the user is safe.