To me a fly off hand brake is a bit different, as it would need the button to be pressed to lock the lever, while it's not held at all if you don't press the button. And you need to press the button again to release it. And whilst it's engaged, the lever is locked, not like in the Esprit. At least it's what I have seen in a late 40s car.
I concluded this was a real fly off hand brake lever but I might be wrong. It's just that it made sense to me as it could have been useful in a hairpin or something as you couldn't lock it as easily as a normal lever? But really I didn't investigate

As for the Esprit it's obviously very useful to lower it to ease the access in the car, but in the Elan I don't really understand why it would interfere with the elbow while driving? And when seating in it, it's not an issue at all?! The centre console is a bit high indeed, but not the lever?
Anyway, I didn't know this S2 feature, thanks!