Bosons, like light, don't like to interact with things. They just want to go places, as fast as they possibly can. So if you want a particle to carry information from point A to point B, light is great. Point it in the right direction and off it goes, and it won't interact with anything unless it absolutely as to.

Fermions, like electrons, love bumping into each other and changing each other. They like to make atoms and collide and bounce off each other all the time. So if you want to build a switch or a microchip where lots of things connect to each other to do some big complicated task like computing lots of math then electrons work really well.

But if you try to get photons to dance together to do something complicated you'll have a hard time. They only interact with each other and the stuff around them when things are just right, and then only in limited ways.

And if you try to use electrons to move data over any kind of distance that's hard too. They're constantly stopping to chat with atoms they find along the way, turning the energy of your message into heat.

How's that?

So, while I’ve never heard this saying before, I assume it’s meaning is that massless particles like photons are best for carrying information around (rather than electrons we are using in circuits today), while the electrons are best for carrying state, like in a switch.

Note, that in networking we have already made that transition by using fiber optics, rather than electric wire to transfer information over longer distances.