I have no idea what are the times for roundup specifically, but the number of days required for last treatment before harvest is routinely shorter for non-organic crops (when the same product can be used for organic and non-organic) - I am not saying it's done the day before either way, but longer is given to organic crops.
And something nice to know if that this minimal amount of days tend to be even shorter when the crop is harvested for animal feed - I was just learning about that from the A&M Agrilife Extension conference I attended last month. So there might be an argument there to say that it would be especially interesting to buy organic when looking at animal feed.
Ultimately, deciding whether the premium you have to pay for organic is worth it is very personal, and depends on what you put in said "worth" (in my case, while recognizing that the organic label is not perfect, I think it is something worth supporting for the ecological benefits alone - if me and my chickens get any tiny health benefit from that choice, cherry on top of the cake, as far as I am concerned!)
But, regardless of all of the above, I would like to point out that the number of studies, policies and reports centering around the problems glyphosate pauses to both the environment and (thought in a somewhat more debated manner) to human health leaves little room to wishful interpretation and certainly does not suggest it's on par with coffee or such.
It is also absolutely not something we cannot do without. There are also a lot of ways to do sustainable, large scale farming that has yield comparable to conventional agriculture while not tilling AND not using a lot of chemicals (certainly not glyphosate!). It's become a bit more talked about nowadays, with ideas of regenerative agriculture. It was kickstarted by a Japanese farmer (
https://en.wikipedia.org/wiki/Masanobu_Fukuoka) I think. Admittedly, regenerative practices and the like do not go as far as this man and do use some chemicals, but very little compared to conventional agriculture and again, certainly not glyphosate.