You misunderstand my criticism. The problem isn't that they're proposing an imperfect algorithm to a problem that's too computationally expensive to solve perfectly. The problem is that what they're proposing is strictly worse than NHST (which is the current status quo).

Look at it this way. If you're testing N different pieces of your site, trying Ni changes for each, and some of the variables are dependent on each other (which is almost certainly the case), then doing local improvements to each part is as likely to make the result worse as it is to make it better. NHST does not have that problem because you switch to a new layout only when you have enough evidence that it increases convergence. So the proposed algorithm is strictly worse than NHST. Not all imperfect algorithms are created equal.