That's if they get your address.
The extra work required on my end to obscure this is just that - extra work. A business is already busy, by definition. I'm not making the claim that it's impossible to keep this private. I'm making the claim that there are more avenues for which this can be abused. Anyone in payroll or purchasing would likely have access to the wallet address. That's more people that I'd have to trust to not abuse the business .. more headaches, as people are largely a finite resource that need to be replaced in business every so often. I wouldn't want to have to keep trusting new people with what would become extremely sensitive information. Why would I?
Also, when people look at the blockchain, all they'll see is someone sent this amount to this address. They'd not know what that is for unless there's a message included.
We both neglected to mention that most purchases are done with having the ip address recorded. They would have a very good clue of my logical location on a network, thereby easily finding out who I am. Again, more headaches and work that needs to be done on my end to protect my business.
And you could easily change address anytime you want.
Sure, see above reasons as to why I'd like not to do this. A bank offers me one or two (likely less than ten) bank accounts. To me this would be telling me that I can just open more bank accounts. Again, more work. Why would I voluntarily put myself in that situation, when it can be done automatically on a protocol level?