The "nut house" refers to another forum and I 'm not going to knock it or anyone else's approach to all things bonsai. And I'm not a well educated historian or bonsai expert - but I have this opinion about comparing trees in pots versus growing trees indoors.
In the earliest discoveries of documented examples of bonsai the apparent desire was to bring nature indoors. This was accomplished by placing various plant material onto slabs of stone. It was found that root pruning (a generalization) and frequent top reduction as well, would keep the trees from growing very large. Planting these materials into ceramic pots would come later on. But the key here is that containing the roots could be easily accomplished without seriously harming the trees.
Now on to the 'indoors' thing. In those earliest times indoors meant something totally different than it does today. We are talking hundreds of years ago - way before glass windows, central air conditioning (HVAC), Home Depot, etc. Before there was a United States of America. Homes in those Asian lands were much more open to nature around them. Bringing trees indoors meant into an open courtyard or to a room with no solid walls, only slats for ventilation.
The concept of growing indoor 'houseplants' came much later. European merchants and travelers visiting exotic tropical destinations discovered the unusual and beautiful flora and brought examples of them home to enjoy and to sell. But the new owners of these plants needed a way to protect these tender beauties from the harsher climates of their homelands. In order to replicate tropical environs they invented glass enclosed conservatories - later on greenhouses. They then loaded these with their tropical plants and trees. In time this evolved into the houseplant industry we have today.
However the earliest bonsai practitioners had the sense to provide as close to a natural environment for their 'potted trees' as possible (weather wise) while still confining the roots. They knew that in nature confined roots happened in the mountains where they gathered these trees - rocky ledges, crevasses and so on. That was natural. What is not natural is bringing these same trees into a 21st century home unless you can provide all the required lighting, humidity, temp fluctuations (especially nighttime), moisture, air-flow, dormancy needs, etc. Not to say that this can not be done - I've seen fabulous examples of hardy trees grown indoors, but it is NOT the same thing as root confinement which is what growing trees in pots amounts to.
Apples and oranges I guess.