That’s a broad topic where I would avoid making generalizations. It’s a matter of tradeoffs.

The key indicators I’d look at are, in no particular order:

• Cost. Does cloud hosting provide economies of scale that dramatically reduce operational costs?
• Risk. If your cloud provider hikes prices or turns out to be based in a hostile fascist dictatorship, can you easily switch to another offering?
• Liability. For better and more often for worse, companies love delegating business because it relieves them of liability if someone cocks it up. It’s a harsh reality that some SMEs have IT infrastructure that looks fine and inexpensive until they find out the hard way that their “IT person” doesn’t know what a firewall is.
• Accounting. Companies strongly prefer OpEx to CapEx due to the way modern accounting incentives, and cloud hosting is tailored to that.
• Practicality. If you want your email to sync to your phone abroad, you’ll need a cloud (though it could be a private cloud, but then I’d recommend a VPN which is more secure but less practical).
• Security. Does the NSA looking at all your files matter? For governments I would hope it does buuuuut…

Either way it goes, be mindful of blind spots. Companies often don’t (IMO) properly assess the risk of locking themselves into walled gardens due to short-termism. But at the same time IT gremlins such as myself tend to underestimate the costs we represent, not just as salaried employees but as people who might cock something up or leave behind us an undocumented mess that will costs hundreds of thousands to rebuild a few years from now.