From the other side, my wife owns a small business where 90% of her sales are on credit cards. She has no desire to encourage cash as we honestly report all income regardless of source (and cash is a hassle and increases theft risk). The ~3% credit card fee is also more than made up for by the higher spend of credit card buyers.

From talking to other business owners, though, the lure of "tax free" cash is definitely a factor.

many such cases. imo it's a skill issue but understand the thought process and why it's so prevalent