When soft contact lenses emerged, only firm lenses could correct astigmatism. If you had less than 1.00 unit (units are “diopters”) of astigmatism it was frequently ignored with fairly good success. This is still true, and many doctors never discuss low astigmatism when they find it in their contact lens patients.
Most soft contact lenses are mass produced, and the custom made soft lenses have not reached the refinement of firm lenses. Soft lens fitting is a process of establishing the most logical fit out of the options available rather than the custom designing and engineering used in firm contact lenses.
That’s not to say that the science of soft contact lenses haven’t come a long way. Good vision can be attained from quite complex mass produced prefabricate soft contact lenses. In fact the advancements in the last 10 to 15 years are uncanny. I once thought astigmatism correcting soft lenses would never be perfected. I was wrong. Many people are well fit with toric soft lenses, i.e. astigmatism correcting lenses.
Still, for many people, firm lenses provide visual intensity not approachable with soft lenses.
So why use soft contact lenses over firm lenses?
In two words, initial comfort. Most first time contact lens wearers find soft contact lenses more comfortable. This is more because of size rather than the softness. Recently there has been a surge back to “scleral” firm lenses. These are firm lenses of large diameters similar to soft lenses. Many find them similarly comfortable.