When people say that it is not worth investing in cloud mining, they are not lying, and it's better to learn now than to learn the hard way.
Theoretically the ROI is possible in a year or two on paper but in practical it's not. You can't make a profit with cloud mining, it was good for only the early birds and those who made profit are the lucky people, now it's not like that so invest with caution.
It is total mystery how bitcoin mining is working. I suspect how it got boomed in 2013 when cex was highly promoted. Because bitcoin mining is a tug of war between running cost is an profitability. Personally I do not have any plan to go for cloud mining. If I get chances I will mine with some powerful miner.
In my understanding, mining will be profitable only for the future speculation. People who are mining and holding bitcoin might find profits with it, for that, we might need big capital to afford running costs.