No, it's a matter of preference. The default fonts in some browsers are pretty ugly, so if you want at least a chance of getting a better font, you can use a stack like this. But it's fine if you don't.
> The default fonts in some browsers are pretty ugly
Is this really the case anymore these days? I think Firefox uses Courier New on Windows as the default monospaced font, but other than that I'm not aware of popular browsers using terrible fonts by default.
A nice aspect of using just serif or sans-serif is that users who configured their browser's font options get what they chose.
