Growing inside of 1l pots

Is it a waste?

It will work for seedlings but anything bigger then that will quickly out grow

you can run them all the way to flower if you want. even a solo cup. You just have to water more often and it becomes a pain in the ass. But yes it can be done

Yes you can. If done properly with enough plants you can get a large yield in a short amount of time 12/12 from seed or a short veg time. You have to stay on top of things. Not much room for error.

1.4 liter pots.