59 megajoules in useful units is 16kWh, less than 2 days use of my house. That's the biggest fusion reaction ever.
Ideally this energy output would be sustained for days within ITER.
JET is not designed to do this, as it has a copper magnet system, which means if you try to sustain such a plasma (confined with around 5 T magnet and around 2 MA plasma current) for longer than a few seconds, you would melt the magnet.
Edit: ITER would operate at 5-10 T, and around 15-20 MA plasma current.
Current fusion devices are not nor were they ever designed to generate electricity for a grid.
This is why we build ITER, and DEMO thereafter. Generating 'usable fusion power' is limited to building reactor scale experiments, which to date, has not been done (ITER will be the first).
DEMO will be plants built independently by several nations following the research from a successful ITER. They will be the first time that any attempt is made to actually convert the fusion products into electricity. There are currently no concrete plans for any DEMO plant - those are contingent upon ITER's success.
If everything goes to plan, the first model DEMO plant would begin operation in 2051. So, as I said, we are a long way away from producing even 1W of usable electrical power from fusion.
Anyway, 59MJ isn't terrible if you can run it at 60Hz. Of course, I agree that the reality is a bit far away.