I have a Chrony Archery unit, it's older but it works just fine. The readout is starting to fade and get hard to read even with a new battery. I may upgrade to the Chrony with the separate display and controls or a CED.. Not sure yet.Reloaders should have a chronograph.
Just because you CAN do something and be successful, doesn't not mean you SHOULD do it that way. To address what BPM said, could you load good ammo? Sure. Will you know how fast it's going? No. Different things effect how your ammo behaves, as I am sure you are well aware. Neck turning, neck tension, neck thickness, weight of brass, type of primer, brand and lot of primer, etc. There are a lot of variables you can change, but you never really know what effect they have on the performance of your finished round. Barrel harmonics change with velocity I want to know how fast those bullets are leaving. Accuracy is often like a sine wave, I like to start slow and ratchet up to max stated loads. The accuracy it will go up and down as you creep through the escalating speeds. At some point (hopefully) one of those speeds will show your best accuracy. "I want to know the velocity at that point." As I change my variables I want to see how that effected the velocity and accuracy. Yes you can shoot enough of that ammo and look at your targets, but I want to know exactly.
If you have gotten along your whole life without one.. Great. Some folks go for the minimalist route. I'm a gadget guy and I like to try things out and see how they can help me. For instance. My indoor range doesn't allow 7.62x25 Tokarev because it is around 1560-1600 ft/sec. So, I cast some 112gr SWC bullets and loaded down to .5 grains over the gun functioning sporadically. Now I have case bullets going 1050 to 1100 fts. I showed the data to the range guy and there is no problem with me shooting that gun.