Not sure which part you're curious about. If it wasn't clear from elsewhere in this thread...
Lambda functions are most useful for very small, straightforward functions that return a value - especially in cases where you don't necessarily need to name or document them deeply, such as for passing as arguments to other functions (for example, sort/sorted).
So if you want terse code that only does what it needs to do and nothing more, pepper with lambdas as needed.
If you want to invent names for things just cause you like inventing them or need to document every single function you write (even if the code is simple enough to document itself), feel free to make all one-line returning functions in the fully named and documented format.