Don't make this game a pure mathematical spreadsheet where you just state that tier bonus simply give you X damage and you don't think about anything more.
The fun and flavor aspect is also important and this set bonusses seem realy cool to see in work. At least you WILL notice when they proc making them feel like another adition to your arsenal.
Set bonus like "gives your serpent sting 5% more damage" are absolutely boring and nothing more than math. Set bonus like this ones we're discussing in this thread are realy cool to have.