The purpose was to punish people for not paying their debts. While friends and family could pay for you (and often had to pay the costs of your incarceration), the main point is to make an example. The philosophy was that debtors really were just lazy or unwilling to do the work. So they were put into gaol so that others might profit from their example. It wasn’t good for creditors in a direct fashion, but, in theory, it deterred people from running up debts they couldn’t pay.
Think about modern loan sharks, who will break your leg if you don’t pay them back. Breaking your leg doesn’t directly profit the lender, either, but knowing that they might do so might encourage you not to fall behind in your payments in the first place.
Correct, or more properly there were no laws recognizing the business as an independent entity. The owners were personally responsible for every penny of debt the business owed.
Maybe you just weren’t motivated enough. Putting you in prison might shake some money loose.
And if you really were unable to pay, then making your life miserable would serve as a warning to others who might be considering defaulting on their debts.
Not entirely true. It was possible to get a royal charter or a private act of Parliament incorporating the company as a legal entity, but that was very difficult and expensive and most all businesses were wither partnerships or sole propriaterships.