If you have a 11-23 cassette you can get a pretty good speed range out of the little 34 ring becasue the cogs are 1T smaller at the end of the cassette compared to one that begins with a 12T.

In other words a 34-13 is only a tiny bit shorter than a 39-14. (both are 3rd smallest cog in the cassette)

The only negative I can really see is that the shift into the smallest cog is slightly larger percentage-wise going from a 12T to an 11T compared to a 13T to a 12T. In reality though this isn't noticeable. Although a 50-11 is a much larger gear than a 53-12.