Remember that cloud is just someone else's computer so, I don't see no difference then using Alby custodial solution. Raspberry pi zero Is a low cost and low electricity consuming device. (0 if running on solar).
Discussion
Hmm 🤔
It's somebody else's computer, but it is completely different to a custodial setup as the hoster does not have access to your keys. Keys and sensitive data is stored encrypted and only available in memory when the node is running.
Now one can say somebody can read the memory, which is correct and applies to anything that is hosted online.
And one can go a step further and say it's also somebody else's OS that we rely on. (if you don't build it yourself 😉 )
So depending on how deep you want to go you rely on something.
But that's why our goal with Alby Hub is to be able to run it in the very different environments to have a solution for whatever the user's requirements are. (from a pi zero to the cloud)