Anything the business can control for: architectural designs, server costs, approaches to building out features / services for the business etc.
When you can mold someone's experience via a new language to model a domain, they become very efficient to it, when they have no prior notions to fall back on.
How many times have developers gone down the wrong path because of X did it this way? type thinking. When you can sufficiently remove that so all that is left to think about is the problem space, you do make more gains around that problem space.
My thesis from (albeit anecdotal) experience, is that when you have developers working in a new paradigm (often, this corresponds with a new language) you have better chances at establishing these things than having to consistently try and override a developers prior notions about how something should work / look.
The trade off is higher ramp times and slower on-boarding, of course. In the short term, it can be more costly.
In what terms, exactly?