anyone ever try one?  https://www.aliexpress.com/item/33043943412.html?spm=a2g0o.productlist.0.0.597d7a39nn1jRj&algo_pvid=9aa00673-86e2-48be-968f-d3611c14226d&algo_expid=9aa00673-86e2-48be-968f-d3611c14226d-49&btsid=52742d0a-e157-4487-929c-84cd86882c2b&ws_ab_test=searchweb0_0%2Csearchweb201602_3%2Csearchweb201603_52

Wow... with magnet retention
The narrow-wide is enough to keep the chain on usually.

I would be surprised such tiny magnets have any effect on the chain, but adding weight and probably loosing some while riding.
That would be interesting to try if you like !

I've always wondered if a strong magnet (such as one from an obsolete hard drive) would help activate lights on an induction loop-maybe the magnetic chainring helps with this as well.