The Mirrored Road into the Interior

So, I was looking at the PHB today. I had never thought through the implications of the weapons size chart. For a medium creature, a small creature's 2 handed weapon becomes a 1 handed weapon, and a tiny creature's 2 handed weapon becomes a light weapon.

2d6 medium becomes 1d10 small or 1d8 tiny.

Critical Ranges and multipliers stay the same.

For 100 gp, a human ranger can dual wield a small and a tiny greatsword, do 1d10 and 1d8 damage and get 2X criticals on a 19-20 and have a light weapon in the off hand. All without having to take exotic weapon proficiency bastard sword.