The only difference is where you put the amp. For active the signal from source to speaker is line level all the way (except for vinyl). For passive you take the amp out of the speaker and put it somewhere else, running an output level cable between.
Oh, and the amp of course. Generally there isn't a whole lot of space inside a speaker and the amp needs to be cooled. So you can't put a big valve amp in a speaker. You also can't have Class A or probably Class AB as there would be too much heat. So you are left with Class D - small size and little heat.
If you like Class D, that's fine. If not.....