Why does node-linker=pnp need symlink=false?

[lishaduck]

It seems to me that PnP is the most "correct" linker.¹ I was investigating turning it on, but the docs say here and here that you should turn off symlink. At that point, what's PNPM giving me over Yarn? I use PNPM because of the reduced size and monorepo management.
To be clear, I'm a happy PNPM user and don't plan on switching to Yarn. I'm just curious why PnP doesn't get the storage benefits. My guess would be that PnP directly uses the global store without needing symlinks, so it still stays small, but then why wouldn't symlink=true just be a no-op?

Footnotes

1. If this is wrong, I'd also be curious to hear about it. I'd assume it's ecosystem compatibility that stops PNPM from using it by default (given the wording "If you are not ready to use PnP yet"). Isn't PnP both faster and stricter? ↩