For what I understand now :
High uptime is good because :
- It means no service interruption (server restart is not instant)
- It means your server has no memory leakage and you do not need someone to monitor it closely (although it is a good practice to monitor it anyway, for example for updates and security)
Frequent restarts can be good because :
- It allows to deal with memory leakage
- It allows to deal with zombie / unkilled threads
- It allow to flush temporary folders, RAM, running process
- It will restart services that may have crashed with no automatic restart
Did I forget something ?
With this, I should take the exclamation mark (!) of htop as a "Congratulation, your server is stable over time" :)