Most monitoring tools ask you to install an agent on every machine. That works for a tidy server room. It doesn't work for lab instruments, older machines, or devices you aren't allowed to change.
Agentless monitoring flips the direction. A central system checks in on each machine using access the machine already offers. Nothing new runs on the machine itself, so there's nothing extra to update or secure.
The same idea works for security. A daily scan finds known vulnerabilities across every network you look after and turns them into a short list of what to fix first.
For small IT teams, the win is peace of mind. Instead of logging in to machines one by one, they start each day with a clear picture.