And roughly 2/3rds of that is lost as waste heat, so really only another 25% is actually useful.

If you don't look at electricity generation, yes. If you look at grid generators, that fraction can get as low as 1/3. (But then, it can get higher than 3/4 on transportation.)

So it really depends on who is counting and how. I do think transportation and heating use more energy than the grid, but I was never able to get a definitive number. (My best guess is it's close to 2 times larger.)

Also, electricity to transportation conversion is usually only around 80% efficient. Making electricity portable has a cost.