Okay, this is a guess I am throwing out with little knowledge on that specific still, but here us what I would say. This is designed to strip volatile substances from aqueous media. If it only goes to 120C I doubt they were planning on getting vapor much hotter than that with the kit. I don't see any way to easily stir the heating flask so it would be fair to say it's for liquid-liquid or liquid-gas media (and mixable ones at that). By the time the boiling point reaches 100, you know you've stripped most of the volatiles that you can from water (assuming no azeotroping). Another thing notable is how small the collection pan is, this probably wasn't used for concentration, as it would mean emptying it regularly.