High intensity will burn more overall calories on a time by time equated basis (more effort = more calories) but can’t be sustained as long as lower intensity,
So, for example, you could do high intensity effort for say 20 mins, and a lower-mid intensity for 60 mins & burn around the same amount overall
High effort will used mostly stored carbs to fuel the SESSION, low effort will use more stored fat to fuel the SESSION,
But when it comes to fat loss, the session isn’t the important part, the overall energy in/out balance is the important part.
EG: you could do a ton of low intensity exercise every day, but if you’re over eating (energy surplus) you won’t lose fat, so the session isn’t the important part, the total balance is the important part (the session is just a contribution)
high > low, takes less time to get the same overall job done, but hard to recover from meaning can’t be performed as often
low > high, takes longer, but easy to recover from & can performed pretty much daily
Hope I’m making sense?