XY mics suffer from having the capsules in a very small geometry?! Isn´t that the whole point of coincident stereo?
Coincident stereo is not necessarily ALWAYS the desirable configuration for "blags" stated purpose to "record some effects". Both of his options limit you to coincident micing. Having the option of a couple of separate mics vs. the coincident-pair in the Zoom would seem to be much more desirable than the "choice" between Tweedledum and Tweedledee.
Isn´t that like saying "AB stereo suffers from having the mics in a very large geometry"?
Not at all. Separate microphones can always be positioned into a coincident pair. But a one-piece coincident mic does NOT offer you the option of separating the sides.