Hanging / Storing Onions

Doesn't make a lot of sense to me that they could somehow draw significant amounts of nutrients down from fading greens. What's the evidence for that? There's a lot of myth in gardening, so I tend to doubt things that are presented as conventional wisdom. I've come across quite a lot of people who actually harvest the greens to use as a crop in their own right, and then claim to have no issues with onion storage. I wonder if it's just come about because the foliage dying back indicates that the bulbs are likely as big as they are going to get, so it's time to lift the bulbs? However, if you are willing to accept slightly smaller bulbs then you could take the green tops before they die back and then potentially get a bigger crop overall. Or perhaps leaving the greens attached reduces the risk of fungal infections before the bulb is fully cured? I suspect there will be some basis to it but I really find the idea of the nutrient draw down hard to believe.

I tried to search for actual evidence on the subject (as opposed to anecdote) but need to find some better search parameters as I'm getting pages about tying raw onion slices to your feet to draw out toxins... Happy to say that one is definitely nonsense! I will have another search when it's not silly o'clock at night.