You'd want to do some sort of test because it can help assess whether your method did better than the alternatives by chance. For example can you really say Met

You'd want to do some sort of test because it can help assess whether your method did better than the alternatives by chance. For example can you really say Method A is better than B if A got 88% accuracy on the holdout set and B got 86% accuracy? Would that be true of all possible datasets? t-test with Bonferroni isn't necessarily the best test for all metrics either.