Seems pretty straightforward. They upsert the lead and then trigger a campaign, and you can do anything you want in the flow.
That’s not necessarily the way I would do it — generally I prefer the Push Lead to Marketo endpoint, which you can then trigger on with Lead is Pushed to Marketo — but it has the same effect. You get full control, they just tell you someone was captured.
P.S. The reason you can’t use other triggers like Added to Program or Data Value Changes is those will not fire repeatedly for the same program/value. You need something where even if there were no material changes to the lead, you still get signaled.