Why were so many expeditions initiated for spices ?

The Chinese government was just as involved in smuggling as was everybody else. The opium trade was undergoing a trade boom, with massive investment. The Chinese had never objected to the trade, with regulation effectively working as an import duty, but did object to the trade boom. The new merchants were hit with a double wammy: a whole mass of new money had just flowed into the trade, and those people were going to go bust. People who had made a massive investment on the basis that the Chinese were ok with the trade deal thought it wrong that the same people were suddenly changing the terms of trade,

That is, they weren’t objecting on the basis that they were free enterprise traders: they were cool with government enterprise and with regulation and with restraint of trade: They wanted certainty, stability, equal treetment under the law, all those non-free-enterprizy things.

Was the certainty of returns on their investments worth peoples’ lives ?

The Chinese court wanted to protect itself and its country from an opioid crisis of massive proportions that was threatening both the country’s prosperity and stability. It’s not like they welched on a deal on bananas out of the blue : their people were dying on their feet. Which might, perhaps, explain why “they’d been ok with opium trade before !” is a disingenuous argument. They didn’t object to the trade when it was just a matter of handfuls of bored nobles smoking up on the weekends. They did object when peasants and craftsmen stopped working altogether, and when their law enforcement officials proved too inefficient (or corrupt, or both) to do anything about the problem.
(also, by definition, the government can’t smuggle ;). Customs officials and cops did participate actively, either by accepting bribes to look some other way or by becoming entrepreneurs themselves ; but that’s not the same thing)

I’m not arguing that opium is good, or even that the Chinese government was wrong to enforce a ban. I was only observing that characterising the objection as free enterprisy was distorting the history.

As is often the case, what business wants is often not free enterprise.