Is it worth using such monitoring systems?

Question

Monitoring

There are systems for monitoring hosts and servers for the lazy. Like PRTG or Veliam. You just set up a server and give admin logins / passwords from servers! Further, the monitoring systems collect all the important information and begin to monitor the servers. This is convenient, but it seems extremely unsafe to me.
Should such systems be trusted at all?
And what if I give the monitoring system logins / passwords from servers within the network, which, behind the firewall from the Internet, still cannot connect to them.

Answer 1

1. If you need to monitor performance and resource metrics, then it is better not to give it to some services, especially those that require access to your servers. Install and use Zabbix / Nagios / Monit. The internet is full of guides.
2. If the monitoring tasks are more specific - for example, you need to monitor that the backup script is running on schedule, then it makes sense to use third-party services. They do not need access to your servers, it is enough for the cron task to send a request to a unique link.
For example, to monitor cron tasks:
https://cronbox.ru
https://cronitor.io
https://cronhub.io
etc.

Answer 2

if the license is honest -
it's safe that Zabbix / Nagios are more customizable, but not the fact that they are more readable, especially by the authorities,
so the question, as always, is in the choice: configuration speed / ease of use / support cost