The sentence is grammatically ambiguous, but common knowledge and reasoning resolves the ambiguity with little conscious involvement. The idea that an ATM would have been invented first only with the intention of serving rollerbladers is pretty far out, and would not be brought to mind. (Not to mention, ATMs predate rollerblades by many years.)
Adding a comma after ATM would suggest a parsing which makes the for rollerbladers nonessential to the core meaning, but the effect is not strong (IMO), and would probably be dismissed by most readers. To get that idea established, against the cognitive bias for the commonplace interpretation (of "first <ATM for rollerbladers>"), would probably additionally require some further marking, such as ...first ATM, for rollerbladers! or ...first ATM, and it was for rollerbladers.