I think that would open up a different safety issue. Suppose you're in a tight turn for some reason, pulling back hard on the yoke, as you have to do in a tight turn. The aircraft is at fairly high angle of attack, but not yet quite enough to enable MCAS. You've got quite a high column load, and you blip the trim upwards to relieve it a bit. If you blip the trim just as MCAS kicks in, and it disables, then you're now flying at high AoA without MCAS protection. You've not trained for that, and your chances of an accelerated stall just went up significantly as the plane no longer flies quite like you trained.
