Is your machine internet connected?
Do you have any open ports?
Do you run everything as root?
If your answers are yes, no, no, and yes than it likely will make no difference. Otherwise (and the last one is just for fun to attempt to show you this is probably not a wise decision) you probably would do better to take this serious.
Exploiting meltdown means you can read all of kernel memory, that destroys any additional layers of protection you might fantasize you had. It means that in memory passwords and encryption keys can be copied. It means that IO between other processes can be spied on. It means that all of the juicy locations to exploit for "return oriented programming" in order to gain local root will be laid bare. And so on.
That's why it's called meltdown. Imagine someone who had hand crafted the equivalent of a modern OS with all of the best practices in place for an internet server. You have kernel address randomization. You have each service running as its own non-privileged user and also in a chroot jail. You have your filesystem permissions locked down tight. And so on. All of that is gone out the window with meltdown, it doesn't matter, because even code running at the lowest possible privilege level can gain access to the contents of any part of kernel memory.
As for "workstation" systems. If you are behind a firewall, you never run untrusted code, and you have JS disabled then potentially you are safe.
Not saying that there isn't a scenario where it would be ok to turn that off, but it's the exception.
So worst case you compile your own kernel