It's applied physics. A study of oscillators, mixers, filters, amplifiers, distributed elements, propagation and algorithms and how to optimize all of these in multiple dimensions. It's community. You can meet interesting people and prepare for and serve during emergencies or experiments. It's travel. You can travel to or contact people in exotic places and have your accomplishments recognized. It's technology. You can create new devices and techniques that perform in ways no one has tried before, or collect and operate vintage machines or the bleeding edge of contemporary gear. It's competition. There are no end of contests across the electromagnetic spectrum using many different protocols and modulation. It's continuity. The ranks of amateur radio are filled with those who earned their living or served their respective nations using similar or sometimes exactly the same skills and equipment.

There was a congressional hearing recently where an ARRL representative was asked why amateur systems function when everything else is down. The answer is simple and compelling; the amateur is the owner, technician and operator of his own station with a deep understanding of every part and what is needed to make it work and how to adapt it. Hard headed self sufficiency. Commercial and broadcast systems die when the backups run out of fuel or the Powers That Be take them away. First responders can't quickly fix or replace their systems when something or someone breaks them. Give amateurs a few watts of power -- by any means available -- and they'll cross oceans or talk to people in space using equipment they can carry at a dead run. It's the last thing that still works when all the other gears strip.

And you are entirely welcome to take part in whatever aspect of it you wish. All you need is a license.

I imagine everyone gets something different out of it. I have my technicians but have never made contact and barely listen. I use it as an excuse to learn electronics. There is a lot of material written for the HAM audience that is great for learning about electronics.

Building radios! Doesn't matter if it's very simple, or very complex, you get enormous satisfaction when it works and you can actually communicate with someone.

Doing experiments outside of a personal lab in a legal way.

I think it's a choice between one of the newer kits and just buying something from eBay that will get you on the air. Any transceiver manufactured in the past 20-30 years will be just fine, and might result in more on the air fun (at least initially) than a low power kit.

uBitx (http://www.hfsignals.com/index.php/ubitx/) is I think $110 for a kit of the guts. People seem to be really enjoying building them.

QRP Labs has a bunch of cool projects (https://qrp-labs.com/qcx.html). CW is something I haven't learned yet, but is pretty attractive for what it can do, how far it can reach on low power.