Just apart from the comment from Slavy, even if security is important to you, it might be useful to patch out to set. So you see here that a patch that is installed too fast can cause problems due to the side effects that were not yet known at the time of publication.
Certainly with Meltdown / Specter one has to be careful, because the patches have the potential to do certain things. to slow down. Critical systems that are designed for a certain peak power can have unpleasant consequences if the peak can no longer be reached.
Information security is more than just confidentiality and integrity. Availability is unfortunately all too often forgotten. There is no golden rule. At most, there is a guideline that everyone must draw up for themselves. Meltdown and Specter are industry-critical, but not so bad for most systems that run everything under a single account (or even worse, all with root / SYSTEM rights). Even though you are already a hacker in a way that you can run your own code, there are probably other vulnerabilities that are easier to use to obtain further rights.