The short answer is yes, it is safe for Radmin VPN to show your IP address because it is not your 'real' IP address.

How is it not my real IP address?

There is a difference in IP addresses. There are local network addresses, and there are public addresses. A local network address is an IP address that is only valid on the local network, whereas a public IP address can be used to pinpoint your geographical location. The IP address listed on Radmin VPN is an IP address that is only tied to your device on that specific Radmin VPN network.

Can people still use it to pinpoint my location?

No, they cannot. Since Radmin VPN is an application that virtualizes a local network, the IP address listed in the app is just an IP address that other people's computers use to route data to your computer through Radmin VPN's servers. Since it is routed through Radmin VPN's servers, it works just like a normal VPN that hides and obscures your real IP address.