> And dropbox just lets you sync files to a remote server.

Whats the point?

Zoom does NOT allow you to share a screen using ultrasonic. This is a lie.

It sends a code like ZOOM-453FHREF then you use this to connect to a server and share a screen using the internet I guess.

There is simply not the bandwidth using this technology on current common hardware to share screens.

I don't understand what you are you claiming, Dropbox doesn't sync files with a server? It at a base level it does that. That's not a lie.

Sending such a small code can be done many ways, as they mention visually to human eyes.

What is interesting is these two methods, ultrasonic and light can't penetrate walls.

What they are doing is defining spaces using technology that can't penetrate walls, this is why it's interesting.