To answer the last first, because it's just easier, growing a houseplent involves little more than keeping it watered, fertilized, and potting UP as it grows. Bonsai culture requires judicious, purposeful pruning, pinching, and root pruning at repotting times in addition to the above. Neither way is necessarily difficult, nor time-consuming; but each is different, producing different results (obviously).
As for care, that can get a bit tricky. One thing that is a MUST for P. 'nana' is that is MUST have a cooler period and doesn't necessarily tolerate extreme heat well. The cooler, dormancy period is probably the most important thing. Lax care elsewhere may or may not lead to the death of the tree, but lack of dormancy definitely will. It might not happen the first year, or even the second, but you'll really be treading on thin ice past year two without that cooler period and the tree may decline rapidly at any moment. This is why they're sold as "cool house" trees. With that said, it's not all that diffeicult to accomplish this in Ohio. If you've a room in your home that gets an eastern, western or southern exposure and also stays somewhere in the low to mid sixties in the winter (not any warmer, cooler down to about fifty being really good), you're probably set. Mine is in a greenhouse/garden window in my kitchen. I place it closest to the outer southern pane, along with other trees that require cooler temps in the winter, like Virginia Live Oak, and Koelreuteria. The temperature in this spot during the winter ranges from 50-65Ã‚ÂºF, mostly staying around 55-60Ã‚ÂºF. It gets progressively warmer closer to the room, but isn't drafty. So, the closer to your windows you get, the cooler it gets (thermal insulating [double paned] windows less so). Beyond that, it should be treated like most indoor trees, skipping fertilizer, or at most only once per month, during dormancy (skipping is better). Mine is in a mix of perlite, humus, bark, and pumice, but soil mix isn't imperative as long as it is not terribly retentive (i.e. no potting soil, must be fast draining).