I have run 2 tanks for several years with only a scrubber. I would say that it can be done but that strongly depends on the the system - mainly, related to corals you will be keeping IMO.
FO of FOWLR, my opinion is you can go scrubber only.
Skimmer + scrubber is a good combo. One thing to remember with skimmers is that you don't want one that is too big for your system (regardless of any other filtration) as it may not work optimally. One thing that I have recommended is that when you put a scrubber and a skimmer together, you can "de-rate" both of them to a degree. So lets say you feed 3 cubes/day to a 120 gallon tank. Normally you would put on a 36 sq in scrubber (3 cube/day) or a skimmer rated for a 120, or maybe a 150g tank. Instead you might put on a 24 sq in scrubber (2 cube/day) and a skimmer rated for a 75 or 100g tank.
But then lets say you are going to stock heavy in SPS. Then I would error high on both - 3 cube/day scrubber and 150g rated skimmer
Of course, the scrubber "rating" or "capacity" will depend greatly on construction. If you're DIYing one, and you're in doubt, add a little to the size and make sure you have enough light and flow (and a rough enough screen)