Hi,
That depend on your needs.
I guess you have Analog Lab and Piano V2.
You do have sounds in Analog Lab from all Arturias soundsource applications like Piano V. But having the individual applications give you the possibility to have full control over the sounds and too create your own sounds. I like to be able to do that.
The full individual applications can both be opened inside analog lab extending the possibilities in Analog Lab, and they can be used by them self outside Analog Lab.
Also i believe you get more factory sounds (also in Analog Lab), if you have the full applications.
The current V-Collection together with Pigments cover all Arturias soundsource products.
Beside that it's possible to buy sounds/ presets that can be used in both Analog Lab and in the individual applications they are made in.
There are many info on the product pages.