I did a diagram. Is it helpful? 
Discussion
Yes, but you should never connect your cold storage to your computer via USB for best practices.
I think it’d need more context for new people, but it covers a lot for a small diagram.
You can have non-custodial wallets on your computer/phone. The keys would just not be consider cold as device is internet connected.
The node can be in the computer. Maybe have a venn diagram?