What is the purpose of the NLSF457 from On-Semi?
Have a look at the NL7SZ57/(SN)74LVC1G57, a "configurable multi-function gate":



If you keep some input(s) constant, you get several possible logic gates from how the output reacts to the other inputs. Its datasheet says:


  The user can choose the logic functions AND, OR, NAND, NOR, XNOR, inverter and buffer.


The NLS457 has four inputs. However, there are so many symmetries that the number of logic functions is not actually larger:

A=0, B=0, C=0: buffer
A=1, B=1, D=1: inverter
A=0, B=0: AND with one inverted input; NOR with one inverted input
A=0, C=0: OR
A=0, D=1: OR with one inverted input; NAND with one inverted input
B=1, D=1: NOR
A=D, B=C: XOR

And the NLS457 lacks Schmitt triggers. Apparently, this device is not meant to be universally usable, and, as the description "special function logic gate" implies, it was probably designed for a specific application for a specific customer, and is sold publicly only because "why not".