costs more to send of course. The postman has to knock at the door and get a signature. It takes time.
It is worth it only if it is essential to know that the piece of mail has arrived, if you need to make sure that the person to whom it is addressed has received it. You can also be sure when it was received.
I have had to send two letters by registered post recently. One was to the ISP company which provides this service. I have asked that they reply by the end of the month. In the normal way I would not give a company so long to provide but I want an undertaking in writing that they will change their training methods - for their own safety as well as that of the customers. It will be interesting to see if I get a response. Any company conscious of the likelihood of litigation should respond positively.
The other letter was much more difficult to write. I had to get legal advice before I sent it. It concerns an area of the law I know nothing about. Looking back on the subject options in law school I cannot recall a subject which even touched on the topic. It had to be worded very carefully. I hope my response helps the person who now has the letter but I rather doubt it will. At least I have done the best I can to help.
The interesting thing though is that I needed to write letters. In both these cases email would not produce results. Even an ISP company will not respond to an email in the same way that they would respond to a letter.
I know someone who is currently trying to preserve an important part of British heritage. Someone else suggested writing a letter to one of those people who might have influence. Yes, the suggestion was "write a letter". There is no point in making a phone call - in this instance they wouldn't be able to talk to the person in question anyway, only his personal secretary. There is no point in sending an email - even if there was an available email address.
Two of my second cousins and I have been emailing one another. I drafted a letter which needs to go to the executors of the estate of the Senior Cat's first cousin. We all needed to decide what would be said in it. Email was useful here. I could send the draft and get their thoughts on it. One cousin added something very useful. The other cousin agreed to the content. We all know exactly what will be said. The first cousin will now sign an actual copy of the letter and send it on to me. I will sign it as well and then post it. Yes, I will post another letter. The executors need this in writing.
Letters are still important. Email is not the same. People still take notice of letters.