Yea, I'm not sure about the US, but a few friends have had their stolen phones immediately used to contact everyone on whatsapp asking for money, sim swapped and tried access for all possible 2FAs on socials, banking, whatever they can get a hold of within the same day. For something so easy to set up as FDE on a computer, or a SIM pin in addition to the phone's passcode (to prevent them from accessing the mobile network, which I forever dismissed but after seeing how they operate I started adding the pin as well), it's a no brainer really.