Purse and hold
The purse is what you have ashore, and it is safe there. The hold is everything since you weighed anchor, and it is the stake. Every chest, every kill and every bad idea that paid off goes in the hold, and it goes to the bottom with her.
It also has a limit: 300◆ in a Sloop, 900◆ in a Brigantine, and none in a Galleon. Whatever does not fit goes back over the side, and nobody watches.
What it costs to carry
Gold is ballast. Every 100◆ aboard costs her a point of evasion and two of flee chance, up to 20 points of evasion. A Galleon does not care, and neither does anyone with Greed's Ballast fitted.
It does make her heavier, which softens the recoil and the parting blow a little. Nobody has ever been glad of that for long.
What can take it
A sinking takes the lot. The Bailiff takes 15% with every hit that lands, and you see it again only if you kill it. Cut Cargo throws it over the side to buy your way out. Revenue cutters have opinions about it. A Sloop that slips a gate meets a writ on the mole.
One more, or home
Further out pays better, and further out is further from home. The hold is why that is a question. Sooner or later you will answer it wrong.