If you build or repair panels with filler, it's a bondo bucket.
If you smooth dings and ripples that would show through paint, and you can still see bare metal over most of the panel, it's part of blocking.
If you use it to conceal poor panel seams or to "align" panels, it's poor workmanship.
It is possible to do all the bodywork without the use of any filler, but you'd either have to do it yourself or be willing to be eaten up by labor costs. A small amount, a cup or two for the whole car, is not a bad thing.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching