I'm not sure I fully understand the whole investing stuff. Maybe it happens this way in real life and im just totally ignorant lol. But with investing, isn't it understood that there are risks? You don't have a guarantee of getting money back, right? So why would the potos dude need to pay everyone back for something out of his control? Is that normal? And why are they saying in this chapter that the crown princess is the only one to benefit?
When people invest... in simple terms they're loaning the Baron a set amount of money, and he agrees to pay it back with some extra. The extra in this case is whatever percent of the profits were promised to each individual noble.
If a large investment fails, yes, it's understood that he won't be able to pay it all back no matter what he does. That's the risk the characters are referring to. It's considered irresponsible and greedy to invest hugely on something you don't know will succeed, because you are still responsible for paying back the money in the way you agreed to do. If it had succeeded he would be very rich, just from the sheer scale of the money the crown princess poured in.
As to why the crown princess benefits, it goes back to the debt trail again. She didn't use her own money, but borrowed from the Temple. So the Baron owes her money and she owes the Temple money.
She's a member of the Imperial family, though, so she isn't being held directly responsible for her debt like the Baron is for his. Instead it's now on the Imperial family as a whole to pay it back.
The 'benefit' is the protection of being a royal, which means that she's not being thrown into debtor's jail or having her possessions seized to pay the missing money back.
It took me a few minutes to wrap my head around the ways everything links up, lol. But they're all nobles so they're more or less used to this kind of convoluted stuff.