Did you ask a lot of questions as a kid?
Its ok.... I did too. AS for the heat welding plastic, I dont do any of this but I suppose it would be a stronger piece than a solvent bond. The issue is that since acrylics are clear, the heat weld could not be done really clean. Acrylic is really cool because it is clear, but Ive come to the realization that this is why it is hard to teach anyone to build with it. All the flaws in workmanship will show.
If we were using high pressure molds, acrylic could be reformed several times. Problem is were not, and any clear mistakes go into the recycle bin!
Sometimes I wish I chose another material :~