I've seen this debate hashed out on food sites for years. The argument against is "why?" and the argument for is "they're taking time out of their otherwise tipped workday". I realized that the division really seems to split on urban vs non-urban.

In the former category people are primarily doing carryout from places built around carryout in that there aren't servers waiting tables and bagging up orders. In the latter category people tend to more frequently do carryout from actual restaurants and in those cases they really are interacting with an otherwise typical server.