It depends on how well the problem is understood. If the problem is your standard MNIST dataset then sure it could very well be a waste of time to sit around and serialize your manual hyper param search. For any new datasets which may or may not be cleaned theres much to be learned from iterating on a very small subset of the data, at that small scale it's much easier to get a handle on the major failings, such as encoding the wrong things or weight explosion.