Do Fortnite V-Bucks and Skins Purchases Save on All Platforms?
The situation here is very ambiguous. The V-bucks you bought on your mobile will only be available on your mobile. And the skins will be available on all gaming platforms, regardless of which platform you purchased them.
Let’s look at the example of buying Inferno pack:
If you buy a skin Inferno with V-bucks on your mobile, then the outfit will be available on all platforms on which you log in from this account. At the same time, you can spend 1000 V-bucks only on a mobile phone, and on other platforms you will not see these 600 V-bucks.
The same situation with other platforms: if you buy V-bucks on the PS4, then they will be available only on it, etc. You cannot spend and see them on other platforms.
So the answer to the question “Do Fortnite V-Bucks Purchases Save on All Platforms?” – No.