Only the helium nucleus is formed as part of the fusion reaction, so it starts off being positively charged, and not later stripped of its electrons. That, in principle, creates a current which can be used almost directly.
Well, it creates a region in space with a high charge density that can be accelerated to a plate that has a voltage applied to it which it bumps into which then causes a current.
Importantly, this doesn't have to happen in the reactor vessel. The charged gas can be pumped somewhere else.
It does have to happen in the reactor vessel. It's not just that it's a charged gas. It's that it's a charged gas which is exploding with almost 300 kWh of energy per shot.
