I'm pretty sure it's a clickbait myth. I cannot see how it would work at all, all you will get is a dead stick of rose or if lucky it may
root from further up, but either way you'll have a tiny rose trying to fight a massive potato plant.
Note that none of the videos actually show it working.
Stick a cut flower into a potato and you will find it wilts almost instantly the potato won't give up the
water it contains magically to the flower, neither will a potato decompose at all in the time the rose would take to root.
A
video on why it won't work, read the description for a bit of science, and the comments for a lot of people trying to defend the method without actually having done it.