Hiya and Welcome!
Yes, the type of surgery needed after massive weight loss is
reconstructive and not what someone typically thinks plastic surgery is all about. (Though, I never had a "normal" body so maybe for me it is more "constructive" construction work than
re-constructive!

)
Because, like you said, exercising is made greatly more difficult (and obviously we don't need something that is physically exerting enough made more strenuous!), the extra skin can be prone to rashes potentially, and psychologically it can be devastating to put so much work into something and feel a bit disappointed at the end result, if not worse.
But, even so, surgery isn't for everyone for a variety of reasons and goodness knows it is NO walk in the park. Surgery days, before and after I check my sanity!
It is the weirdest sensation to long for something and dread it at the same time. But, then again I guess surgery is very similar to weight loss in that respect: You have to be able to make some immediate sacrifices for a much more desired long term result.
Oooopps, I think I may just have gone a'rambling!!