Not to Disagree with JAM07Sport, but I have been running a V3 for years. I shot it once and bought a new bayonet. I lost it in a home fire, and they replaced the entire unit at no cost. Had a controller go out and they replaced it no charge. In my experience, their customer service is first rate.
To your question:
A chrono is not necessary, but will pay for itself many times over in component cost and time if used consistently, with good data collection.
If you choose to use a "shoot through" type, get one that has its own lighting, as they provide much more accurate and consistent data.
Personally, if I am not shooting a match, I have the V3 mounted (off barrel). If you get the Lab Radar, get a remote trigger (I almost sold mine due to lack of data collection). The trigger reads 95%+ of my shots.