Yes, I agree.
“Thank you” is more polite as defined in the Oxford Collocations dictionary for students of English.
This dictionary tells that they r both formal.
In slang and informality, we may use cheers even with people whom we don t no.
As 2 conclude, both are used as adjectives, verbs, but more as nouns.
In brief, our contributor deserves a special THANK YOU for her final line.