It's an expensive chrono, but very easy to setup and use. Really handy, if you cannot go down range. When I first started reloading, before I joined a gun club, I used a public range, where one cannot go down range to set things up. The LabRadar was perfect.
With regards to reloading, it is common practice to start with a load that is on the low end for the powder (using manufacturer's recommendations) and bullet used, and then work up until you get the desired results, based on your application (e.g. power factor for competitive shooting, felt recoil, accuracy).
A chronograph will allow you to objectively measure your performance and help prevent you from straying into dangerous pressure levels. A very important tool. Not something you should rely on "by feel", IMHO.