The only way someone could use that phone after you use it is if they cut your thumb off to scan.
I don’t use thumb scan or pin numbers or swipe entry. I tap the On button and I’m good to go. I just don’t put anything on my phone that can be mis-used by a thief or anybody else...no saved passwords, no account numbers, etc. There are links to account log-ins...but that’s all they get. I’ve even removed a lot of the bloatware. Would it be a nuisance if it got gone? Yep. But a quick call to Version shuts it down.