@ventisca I'd say it would be fairly impractical as a weapon. It was designed over the ages for a single purpose, which wasn't killing animals/humans. It was meant to cut hay/weeds/crops and such sort of relatively soft plant matter. The fact the edge is on the inside and it curves inwards means the opponent needs to be, in a manner of speaking, between you and your weapon for it to be effective. In other words, there's nothing between you and the enemy while you are in the process of cutting him down. Of course if the blade doesn't hit, the shaft might hit, but it wouldn't amount to much. As a weapon it would be also fairly cumbersome and easy to break. No stabbing either.
I have used a scythe for many hours in my life to clear roadsides, so I'm not talking 100% theory here. It's good for what it's meant for, but as a weapon it would be best left to the Grim Reaper and his symbolism.