Because I was told to! 
To me, some things just SCREAM
this was fixed by a hack. Silicone in plumbing in chief among those things. You could use silicone, you could tig it...if you want a seal that can be broken for future repair, use the putty.
Plus all the green weenies will
to you for using a green product...it wasn't meant to be green, just turned out that way...it's pretty much oil (linseed or fish) and clay or finely ground limestone.
