Give buyers limited access to plugin admin - need advice

I see quite often plugins which, in the live demo, give limited admin access to buyers to see the plugin admin side. I want to do the same.

How do you do that?

Manually? Using a plugin?

Is that harmful? Does it affect the website?
Do you have to put backups back periodically?

What I did was create a non-admin user and modify the plugin to allow access by that user. If I remember correctly there is also a setting to disable users editing their profiles.

If you want to allow user input on your plugin, then a backup system might work, but this could be vulnerable to abuse (e.g. posting inappropriate things on a live demo). I personally modified my plugins so any changes they tried to submit were ignored.

This way, they can get a feel for the plugin without me having to worry about abuse or resetting plugin data…