Using such proprietary features sounds like a great way to subject yourself to vendor lock in and leave you vulnerable to your cloud provider's every whim. I understand that using ready made features is alluring, but at what point are you too dependent on somebody else? All these cloud services reminds me a bit of left-pad, how many external dependencies can you afford? Maybe I'm too suspicious and cynical, but then I read articles like these from time to time...
The difference, IMO, is that you're generally leveraging the cloud providers platform in addition to using their hosting.
There are ways to make the hosting relatively agnostic, but choosing a pub/sub solution (for example), that operates at 'web scale' will have a distinct impact on your solutions and force you into their ecosystem to maximize value. Why bother with BigCorps UltraResistant services if you're only going to use some small percentage of the capabilities?
I've made systems that abstract away the difference entirely, but I think the 'goldilocks zone' is abstracted core domain logic that will run on anything, and then going whole-hog on each individual environment. Accept that "cloud" is vendor lockin, and mitigate that threat at the level of deployment (multi-cloud, multi-stack), rather than just the application.
You're not alone. I worry the same about many things, but everyone just thinks I'm a negative nancy for discounting THIS AWESOME SERVICE with these awesome, 100% non evil people behind it!
