It will not scare away bots but 10 seconds of wait (CPU or only a sleep) will turn away many real users. "This site is so slow, I'll use something else." A kind of reverse captcha.

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Hnrobert42 an hour ago | parent | next [-]

Maybe, the proof of work can run in the background.

	▲	btown 10 minutes ago \| parent [-]
		Or it can run as part of a checkout wizard's "verifying your browser and processing your payment, don't close your tab" step.

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2 hours ago | parent | prev [-]

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