There are residential non-SRA d appraisers who competently perform high-value/difficult "sophisticated" appraisals. However, the SRA shows proof the appraiser has made a considerable effort to get it, and for prestige, they are hired in certain situations like: trust departments of banks,Tax/IRS work, manager at an AMC or a federal agency, and certain legal work. And it could lead those good at networking to referrals from Cert Gens in the AI division..
I believe it takes a certain kind of person to pursue it and also to benefit from it.
Does it make one a better appraiser? I don't know. I think if one is ethically challenged or lacks common sense, getting designated won't change that. If one is competent, it will make them even better. The courses do teach good narrative writing skills.
When I used to do reviews back in the day, I reviewed two reports from two different SRA appraisers. Of course, the reports that make it to a review are usually pre-flagged by somebody. Each SRA report turned out to be a problem child -, but both were well-written and LONG. Padded with narrative, much of it superfluous. One report was so long it was painful to read. It had back story of the region going back to the settlers, followed by a kind of travel brochure description, block by block. Pages and pages of it. But in the end, his horrible comp choice and ignoring more similar proximate comps made the results no better than an ordinary report that had the same fundamental problem.