This is a loose comparison, but stick with it.
The official jump gate network in Sirius is maintained, regulated, and mapped. The Jump Gate Consortium and Ageira Technologies operate it. Every gate is on the nav map. Trade lane entry points are marked. The system is clean, fast, and controlled. It is the corporate-approved route between systems.
Jump holes are everything else.
They are unstable natural wormholes — unmaintained, unmapped by official sources, dangerous to navigate, and scattered across the sector in places the houses would rather you didn't go. You won't find a jump hole on the standard nav map. You find one because a bartender mentioned it, or because you flew into an uncharted region of a system and got close enough to see the visual effect. Or because you knew exactly where to look because someone on a forum told you.
And on the other side of jump holes: the best ships in the game. The highest-paying smuggling runs. Criminal bases that the police don't reach. Lore fragments that the campaign never delivers. The Sabre, the Eagle, the Titan — all of them gated behind access that requires either jump holes or the rep to dock somewhere the trade lanes don't reach.
The authorities don't want you using jump holes. They can't police them. They can't tax the trade that flows through them. The criminal economy of Sirius runs on them.
This is basically the early internet: an unregulated parallel network, full of things the official system doesn't know about, requiring insider knowledge to navigate, and leading to some of the most interesting places in the sector. Dangerous if you don't know what you're doing. Remarkably useful if you do.
A specific one worth finding early: the jump hole in the Tohoku system that connects to Sigma-13, one of the most profitable mid-game trade routes for players who know the route. The gas miners in Sigma space pay well for supplies, and the return cargo is in high demand in Kusari. No trade lane will take you there.
You have to know where to look.