There is always an element of business travel that is not really necessary but its hard line to draw between beneficial and essential. There are also events like conferences where most of the attendees dont' actually attend but meet with peers from other companies and do business just because lot of peopel from one industry are in the same place. Ie the conference itself isnt really 'necessary' but its a good opportunity to meet clients and suppliers without doing separate trips.
Video links are usually fine for inside the company work and some external stuff but many cultures like the physical presence bit .
So i can see the rule reducing things but perhaps not by that much, while working on the plane is sometimes a good idea for many a flight is an opportunity to have a rest and serious think which can be a rarity in todays world.
very hard to keep ahead of the bad guys but as I ahave said before it is foolish of the USA to make such restrictions when there is just as much risk from flying domestic US which always seems to have the lowest level of security in spite of being the proven biggest area of risk