When, during the Pandemic, it became necessary for those businesses to offer another way for customers to shop - I think that the grocery stores and other stores offering curb side deliveries were hiring people FOR that job (or were utilizing employees they already had) so the employees were already getting paid to DO THAT JOB. The stores are compensating their employees, so I'm not sure why tips should be considered as necessary for the service.
In my job - I get paid to do the job I do. If someone from the public comes into the office and I help them - there's no jar on my counter soliciting for tips.
If a person wants to do that, I guess it's okay, but I wouldn't do it.