They're really not that bad as pets.
Even my Western Diamondback named Nippy stopped rattling at me when he got used to my presence and would let me pet him. He would still rattle at my roommates though when they got near the enclosure. He wasn't used to them because they didn't interact with him and they smelled different than me to the snake. While I used a hook to take him out of his enclosure, once out, he was very easy to manage and surprisingly gentle. Not once did he strike at anyone. This was qualitatively different from a wild animal driven entirely by instinct. I also knew someone in Texas that kept a Timber Rattlesnake, and he showed me a neat little trick: hand feeding him using live prey without being bitten. That Timber was well behaved and would just chill on your neck. Venom glands and fangs of both snakes were fully intact, and they were both very handle-able, gentle, and otherwise well behaved.
You won't be able to do any of that with a wild animal. Professional herpetologists are trained NOT to ever do this with captive hots and will generally look down upon this as foolish behavior(at best), but these animals really are to some extent tamable. It's just that no matter how tame it is, it's still a rattlesnake, with all of its instincts and behavioral proclivities intact. Its instinct is to bite when its heat-sensing pits detect a warm-blooded mammal or a potential predator is sufficiently close and/or when its Jacobsons organ detects the scent of a prey item or potential predator. Those pets I interacted with were making a decision NOT to bite the humans interacting with them, in spite of their instincts, and there was definitely some level of trust present on the animals part. If there wasn't, I'd have gotten bitten, many times over.
You can tell that a wild rattlesnake is something entirely different altogether. Generally, those will bite without any hesitation once sufficiently agitated, and once they do, it's a matter of how much venom they decide to deliver. It won't know that you stepped on it as an accident, or that you aren't a predator trying to eat it. And surprise: now you're looking at an extremely painful bite, 6-figure medical debt, perhaps amputation of digits and/or limbs, and even possible death.
Definitely not a pet for everyone. I would gladly keep another.
