Yes $1 holds/charges are typical to ensure a payment actually goes through. Even legit charges like gas stations will do such a thing just to ensure the card is actually open before dispensing fuel, but before the final payment value is known.
It's most likely just a shotgun number check for any card that's valid using a virus-compromised PoS at that restaurant (so the scammers have some access to the payment processor that won't hurt them when it's inevitably shut down for running too many cards)
There's also some scam calls that will run you through voice prompts to try and get you to say the word "yes". They can then use that word "yes" to count as agreement to whatever they want, whether it's signing up for spam, or allowing a fradulent charge- even if the menus preceeding it are unrelated, it makes it a little harder legally to go after them because "ohhh well you said yes to it..."
If you care to, could honestly be worth calling the restaurant manager and telling them about the unusual charge (if the restaurant even exists). They may not know their PoS computer has been turned into a zombie bot for card checking- and it might be skimming their customer's cards too.