I know nothing about electricity
So you figured you'd post your suggestion on /. instead of attempting even the most cursory self-directed research. Gotcha. Laziness for the win.
Is it just that we're so used to designing electronics etc. to use AC, or are there other benefits?
Its easier to transmit long distances, at high voltages.
Its trivial to step up and down to different voltage levels via transformers. The equivalent in DC is not simple.
Mechanical AC generators are simpler and cheaper to build and maintain. And nearly all electicity is generated from mechanical sources (turbines).
Hydro and tidal are water driven turbines. Coal, wood, biomass (methane), natural gas, nuclear, even geothermal electricity are all "steam driving turbine" eleciticity generators, wind is an air driven turbine.
That leaves solar, which IS DC. Worldwide, like 0.2% of electricy is from solar.
Batteries too, are DC, but are charged nearly exclusively from AC sources.
then why not put effort into designing AC sources of electricity?
I guess so. I mean, only 99.8% of electricity comes from AC sources. Just imagine what they could do if they put some effort into designing some AC sources, right? :p