This is an unofficial Android front end to Nmap, the network scanner, rather than a reimplementation of it. The scanning is performed by the actual tool, and the application provides a way to construct and run commands on a device.
Because the underlying binary is the genuine one, the capability available is the capability Nmap has, including the range of scan types, service and version detection, operating system fingerprinting, and the scripting engine that extends it into vulnerability checks and service enumeration. The interface assists with building a command rather than replacing it, so knowledge of the syntax remains necessary and transfers directly from any other platform. That design decision is the right one for the audience, since anyone reaching for this already knows what they want to run and needs a way to run it from a phone while standing in front of the equipment in question, which is precisely the situation where carrying a laptop is inconvenient and the answer is needed immediately.
Two constraints are worth knowing. Some scan types require privileges an unrooted device does not grant, so the available options are narrower than on a workstation. And scanning networks without authorisation is unlawful in most jurisdictions regardless of the device used, which the portability of a phone makes easier to forget.