Lang-8 (http://lang-8.com) is awesome. You can post anything there, not only your Korean sentences for correction by native Korean, but also: questions about grammar, question about meaning of words, request for transcription, anything.
I asked about -는 것만 하겠어? today on Lang-8, and very soon I got 5 responses from 5 different people and they all explained slightly differently. Hahaha. But I think I got it.
This is from TOPIK 32 Advanced, Listening, no. 2.
Have you downloaded the problem & answer key set yet?
Man: I saw digital images of world famous paintings, and they were more dazzling than the real ones. From now on we don’t have to go to art museums.
Woman: No matter how advanced technology has improved, would it be comparable to/better than going directly and seeing the paintings with your own eyes? (I believe it wouldn’t.)
The answer is no. 2.
From what I understand, -는 것만 하겠어? is an affirmation disguised as a question. ;P So the speaker is making a statement that she thinks whatever is attached to the -는 것만 하겠어? is BETTER or THE BEST option. ###