First of all, if you go that route, you will most likely end up with a good beer that you will enjoy. So, not much downside.
My beef with using extracts that way is that you don't really know what they used to get the color and flavor. Like I said, maybe you don't need to know. But if you want to get scientific, or go all-grain, it's tough.
I once converted a recipe to all-grain that called for amber LME. The Breiss website said that they used 2-row, munich, and C-60. So I pulled some percentages out of thin air, and made the batch. It came out great, but it was just a bunch of guesses. Part of the fun, for sure.
Cheers!