Why virtual-store-dir needs to be unique for each project ?

[tolotrasamuel]

virtual-store-dir

The documentation https://pnpm.io/npmrc#virtual-store-dir says:

NOTE: the virtual store cannot be shared between several projects. Every project should have its own virtual store (except for in workspaces where the root is shared).

But why ? Can you provide an example of why it cannot be shared between projects?

I am asking because I checked its content:

I see that all folder are versioned,
For example:
[email protected] depends on [email protected] . How can this ever be an issue if it is shared between projects ?