Way back I used plain old spackle. It works fine. I even made large fillets on pattern planes with it. Tight ones, not so good! Filling low spots should work but, as mentioned not recommended. I might go back to it for ding and minor imperfection work. Sands good and only shrinks once. This is the USG green label. The light weight stuff (blue)was the one that got attacked by dope. Now, there are multiple grades but I believe the green is still the same. I only use it on my walls now. I had graduated to Micro balloons and now super fill.
Tom