Here's why:

* Copper(I) ions (Cu+) are unstable in aqueous solutions. They readily disproportionate, meaning they react with themselves to form copper(II) ions (Cu2+) and metallic copper (Cu):

2 Cu+ → Cu2+ + Cu

* Bisulfate ions (HSO4-) are acidic. They would react with copper(I) ions, further promoting the disproportionation reaction.

Therefore, attempting to form copper(I) bisulfate would likely result in a mixture of copper(II) sulfate, copper metal, and sulfuric acid.