That is interesting. I have always just used the Sky Priority line. Were you flying from ATL? I remember reading an article talking about the dedicated bag drop for Touchless ID at ATL, I think it was mentioned being in the basement somewhere and have never tried to find it.
Being able to use the Sky Priority line and booking exit rows are the only real benefit of being Silver Medallion with Delta.
Interacting with a person to check your bag, you should be asked to show a physical ID. The OP should have been asked to show their ID.
The Touchless ID line for TSA is almost always a bit shorter than the regular PreCheck line at ATL, though it does tend to share a TSA agent with the CLEAR people.
You can also use a digital ID in the regular PreCheck line at ATL and other airports but that always seems to throw the TSA agent off as not many travelers use Digital ID. Plus the steps needed actually take longer than actually handing over a physical ID.
You have to tap your phone, then double click the side button, then you have to use face ID or touch ID to consent to share your ID with the TSA, then tap again. All while the TSA agent is getting annoyed asking for your ID that you have not handed over. Then I have had to tell them to check their monitor.