Activating plugins on multisite

Hi,

I have a question. I've red the manual about activating plugins in a multisite on a per site base: Network Admin >> All Sites >> Dashboard of site A >> Plugins >> click activate

So I followed these steps and noticed something I'd like to verify.

Is it true that the plugin menu of the individual site only shows the plugins that don't need to be network activated?

For example: two plugins are both not network activated: Affiliate and Snapshots.

When I visit the plugin menu of the individual site (on the way described above and in the manual), I do see an option to activate the "affiliate" plugin, but I don't see an option to activate the "snapshot" plugin.

The same goes for "Admin Panel Tips" which is shown in the Network admin plugin screen to network activate but it's not possible to activate on a per site base.

Can you please explain to me what exactly causes the difference? I just want to learn why this is so I can understand better.

Thanks!

Kind regards,
Steven