Alright, let's say you try doing that but it fails for some reason. Where did the failure occur? Were you able to open a TCP connection but you received garbage data that your minecraft-ping command didn't understand? Were you able to open a TCP connection but you received no reply to your ping? Did you fail to open a TCP connection (no SYNACK in response to your SYN)?
All of those problems have different root causes and therefore have different solutions. Telnet helps you figure out where in the stack the failure is occurring.