I think it comes down to who the tax authority sees as being the source of the funds. It seems in the UK, at least, the payer to the charity is the donor and, if that donor is a company, they get a corporate tax break for it.

The charity gets their money either way (otherwise would be fraud), but the company isn't necessarily doing it out of the goodness of their heart: their tax bill goes down as a direct result.

Personally, I think the recipient charity getting the benefit of all those rounding up transactions is a good thing overall. But my original comment was about not allowing yourself to believe a comfortable lie: it's business, not philanthropy. Or perhaps, philanthropy in the typical rich benefactor style of giving - it's still a mutually beneficial transaction.