Because it's presumably beneficial. It gives your lawyers extra time to prepare for the case or to potentially settle on more favorable terms.

If you have a right to both a fair trial and a speedy trial, there should be no trial that does not provide both.

	▲	mikkupikku 5 hours ago \| parent [-]
		The speed which enables the most fair outcome overall is subject to interpretation. More time to prepare your case is probably good, but the longer the process drags out, the greater portion of your finite life you've lost to the process. Weighing these two factors, with all the other various factors, can't be done objectively for a generalized case that can apply to all real cases, hence giving the accused some amount of say over the matter.

wat10000 6 hours ago | parent | prev [-]

Waiving your right not to be a slave could be beneficial too.

You can become someone's slave if you really want to. The only part that can't be enforced is you can't be coerced to stay.

Plenty of cults have slaves in the US. But because the are willing, nothing is done about it.

Heck, plenty of us companies still rely on slave labor. Look at Aramark's use of prisoners, for example.

	▲	wat10000 5 hours ago \| parent [-]
		That's an explicit carveout in the Constitution allowing slavery as punishment for a crime, not someone waiving their rights.

wat10000 3 hours ago | parent | prev [-]

This reminds me of Futurama:

"You know the worst thing about being a slave? They make you work, but they don't pay you or let you go."

"That's the only thing about being a slave!"

So yeah, you can legally be a slave as long as you leave out the one part that makes it slavery.