I’ve been using a limited palette for a number of years, cadmium yellow, cadmium red, alizarin crimson and ultramarine blue. It started as a reason to get rid of some colors on the palette and to try and achieve a little color harmony.
For a while I got paintings that were mostly secondary colors, too green or orange. After a time and a lot of help I started using all three primaries in every mixture with one predominate color. That allowed me to control the intensity of the color plus I could make innumerable subtle color changes by just adding more of the predominate color or the other two remaining primaries.
It was helpful to make color charts to see how far I could go with all the subtle variations. I did sacrifice the pop that a prussian blue would give a sky or colbalt violet would give a shadow, but the color harmony and the subtle grays you can achieve is worth it.
So more color without all those tubes.