Exo-Terra bark.....?

[Albatross]

I went to a petshop, and thankfully didn't buy a substrate yet, as I later found out bark is a horrible substrate for any snake. Well... then I came across a video on expertvillage.com or something like that, and one of these people has had her corn for 10 years, and she uses reptile bark. She says it's been treated and... it's good as it retains moisture and stuff. In snake forums, I read so many time not to use bark as a subtrate. I don't see the big deal if it's storebought reptile bark. O.O
People say snakes can't burrow under bark... but... these reptile bark pieces are small. They are like 1 inch long.