When you use an acid to neutralize a base, the neutralized hydroxyls are being replaced by the anion of the acid. Sulfuric acid makes sulphate, hydrochloric acid makes chloride, phosphoric acid makes phosphate, citric acid makes citrate. The reason phosphoric acid is usually preferred is the large amount of phosphate already present in the malt. If your water is low in sulfate, sulfuric acid might be a good idea. Same with hydrochloric.
I don't know what citrate taste like, but my guess is if it tasted good in beer, people would use it over other acids.