If you sell product with a gross margin of 15%, then you lose money giving more than maybe a 10% discount. If you are a freelancer, for example, you might still do fine giving a 40% or whatever discount if the client pays in bitcoin.

But not for every sale and forever, but as maybe a door opener.

Normal discount for bitcoin of 3% (around what fees exist for accepting credit / debit cards) or 5% even, might give customers incentive to pay in bitcoin.