I don't know if "helped art" is a well-defined concept because it depends on a notion of "better" or "worse" art which is itself famously poorly defined.

If all you wanted was a reasonable facsimile of a family member, then photography made attaining that object dramatically cheaper. Prior to photography, almost all of images of people are of fabulously wealthy and powerful people because they were the only ones who could afford a skilled painter making their portrait. After photography, most people could afford a daguerreotype.

The impact on fine art is much more complex. I think probably all you can say definitively is that the timeline where photography exists produces very different fine art paintings because the incentive structure and the implications are different in a world with photos. But better or worse? Impossible to say.