Blockchain is simply a collection of public records and so it's possible to find a use for it in some businesses. I mean, the inhabitants of Yap island used a primitive version which they use to buy and sell houses and other stuff.
Of course, whether it's possible for a business to use would depend on what their business is about. It would be not of much use to the customer end of a grocery chain (store or online) for example but they might adapt it to managing their inventory across branches and warehouses. In this case it would not be about transparency but so that everyone in the chain knows where something is.
I do not understand the usefulness of the blockchain techologies for a regular company or office. Any ideas?
I think that blockchain techologies are worthless for an ordinary company until operations in it are legally confirmed by a goverment.
You must be mistaking blockchain for bitcoins. Bitcoin is just another product that uses blockchain technology, which in itself is not illegal in any country.