Yes, the single share is actually the default backup option. I tried it out last night. After backing up the wallet, I reformatted the Trezor and tried restoring it from the 20 word list and it worked. I guess I'm not understanding the advantage of this over a regular 12 or 24 word backup.
It has no advantage at all to the normal 12 to 24 word backups. The 12 word seed phrase is enough for your coins security. And as dkbit98 posted, you can add passphrase with it which has been the good option that I always go for while generating wallet. Seed phrase backup is advisable.