I don't think any one answered your last question in the original post. With metal siding, you wouldn't know if you have a leak until you see the indication on the inside somewhere... which might be just as bad as the "other construction". The difference being as others suggest, the repair might be easier to take care of especially "cosmetically".
Not sure about the "run advice", I think it depends on a number of factors; size of area impacted, whether the leak(s) have been addressed, overall appearance, long term stability, price and age among others. To me, given what has been described, I don't think the price offered warrants taking a chance that the problems have or can be mitigated.