I used to often use those airline-provided AirFones and AirOne type phones on my US flights for brief voice calls (as in arranging for being picked up or other tasks). But some people would hold long conversations or listen in on conference calls -- and I'm guilty of the latter -- using those seat-back/arm-rest/cabin wall-mounted phones provided by the airlines. Some major international airlines still may have their in-built entertainment system controllers having dial pads with phone-call dialing in mind.

Many major airlines seemed fine with voice calls on board when it was seen as a potential revenue source for the airline. That was when the passenger's cost for using the service was high but the airline's cost to have such service/products wasn't seen as high to the airline. Eventually most of those airlines with such systems decided to ditch these kind of in-flight telephone systems because of too little phone call revenue coming their way and finding cheaper/better uses for "the space" those systems/devices were taking on planes. The AirFone type systems weren't removed by these airlines because of passenger complaints about the calls being disruptive; they were removed because people weren't using them enough.

Now the airlines don't want voice and video calls in-flight because the relatively cheap in-flight wifi and prevalence of lots of smartphones/tablets/laptops could make in-flight calling more generally "disturbing" without providing a financial gain to the airlines.

How disturbing is a video call with communication in sign language? Please let me know, if you can.