1. In most cases it is legal. There are some limitations but they mainly involve needing witnesses for some type of documents.
2. See 1. Also some organisations are just behind the times. If you want to do business with them, it needs to be done on their terms or they will not proceed. You will not be able to convince a middle level manager, or some senior managers to change their blanket policy because you ask them to. 'Chances are their legal team would need to agree to the change and in many cases, the legal team will be too busy to even give it a second thought. It is happening, just not as fast as many people would like.