I've subscribed to Lightroom iphone app does that mean I can use on desktop too?

I have the mobile iPhone app and pay £4.49 per month - is this totally separate to the subscription I see I can join for £9.99 a month on here (i.e. not via Apple app store) yet if I sign up here I can use both desktop and mobile app? i.e. is the mobule subscription through Apple considered totally separate to signing up here? So confused!