If any artists still communicate with clients via FA: don’t do that I don’t feel very sorry for them. This has happened countless times.
That's a nice dream, but in the real world things work differently. If we artists tried to force every customer to only communicate with us via channels outside of FA, we would go out of business.
Don't get me wrong, I agree that FA notes is not a very good platform for this, especially because if FA goes down you can't access older correspondence either, and this is why I have a private Trello board with a card for each commission, and every important detail noted in that card.
BUT... Customer relations 101: When you offer a service, you are accommodating your customers' needs and habits first (within reason), and not the other way around. This is the N°1 rule of service providing - they want to give you money, they want to provide your daily bread, so you treat them with respect and flexibility. You don't go around and tell people "don't talk to me about commissions via FA notes" unless you want to lose all your business and build a reputation of being arrogant and inflexible. You can ask them nicely,
AFTER they contacted you one way or the other, if they can add you on Skype, or whatever channel you personally prefer.
But people have their own ways, some will want to stick with FA notes, some will want to use Facebook, others would want Skype, Telegram, Whatsapp, Email or pigeons and smoke signals - and you can't force them. And it is already very time consuming and exhausting to keep correspondence with several people at once, and the more channels you fragment your communications to the worse it gets. So generally, to keep everything neat and well organized, it's best to use as few different channels as possible. Chose one, or at worst two channels you respectfully ask your customers to use and if neither works for them let them use notes - just save every important detail from them to some outside place like Trello, Google docs, etc.
So next time you want to educate artists about conducting business, get informed about the basics of customer relations first.