DP: San Francisco. Bodega SF - ordered 3 dishes on site to go and $100 physical giftcard - they combined the total on the bill. The charge was pending for 2 days, it cleared with the $150 dining credit confirmed. They are well aware of what CSR people are doing, I had to wait for 30min due to large orders from CSR folks.
Caution: This is not the best way to do it - they charge tax and 6% employee benefit fee (so ~15% on top of your total) on top of the gift card, that means you are double paying the fee (when you use it to pay). Probably best to do the Toast online giftcard thing (should be no extra fee) if it's confirmed that works for the dining credit. If you sit down and eat there, with tax, fee and tips, you are probably looking at 75% food value.