Earlier quoted context omitted.
Mainly because your employees, suppliers, and landlord have no desire to be paid in Bitcoin.
What does that matter? You can convert Bitcoin into cash. But then you can do that in an undisclosed location at your leisure instead of keeping a mountain of cash in your publicly advertised storefront location and becoming a huge robbery target. Also, it doesn't seem like it would be that hard to find someone to accept it as payment, since they can convert it to cash too. And the sort of landlords/suppliers/employe…
If you're going through all that hassle, it's much easier just to be a cash-only business in the first place.