Why would anyone trust a random person to access their device anyway? No matter what problem you are facing, if you know you have assets in your computer, or private information that no one should ever see, you shouldn't be giving access to your device to someone only to fix something in it. First of all, with the advent of the internet and search engines, one doesn't even need external support for small things, especially if they are software-related, secondly, even if someone wants to get some support, they should at least do something to safeguard their stuff before they go for it.

It's never a good idea to give someone access to your device over the phone. If you want to get support, go get someone physically and bring them with you so that they can help you get everything fixed, and while they are doing it, be there and watch everything they do, but even then, you shouldn't have private stuff in it.