The rest of the tomato plants needed to get out of their little cells and into the sunshine. These larger pots will give them enough space for their roots to expand in the next few weeks before they go into their permanent homes in the garden.
Our very kind neighbor, who happens to work in agriculture, gave us several flats of these 3inch pots. Not as big as the first ones we transplanted, but much easier to move around
(and less tippy).