There seems to be some confusion between both your referencing to IP tracking with respect to multiple logins. While you are taking it in the context of geo-restriction wherein Netflix would know if an account from one country is being logged in on a device outside that country and thus it would restrict the catalogue available based on that region. What
@StoriesWithPK is referencing to is the latest update by Netflix whereby it tracks the IP address of your home WiFi to specifically pin your account to your home not just your country of usage, such that if the same account were to be logged in on a TV in even your neighbours house using a different WiFi network it would consider that as password sharing and that would be restricted. Even if a father and son are living Nextdoor to each other but have separate home WiFi networks then it will still be restricted by Netflix after the latest crackdown. And a similar course of action will be taken by Disney+ next year.
As for your question about limiting the number of simultaneously logged in devices by Disney+ Hotstar and still having more number of profiles, it could simply be intended for the living room common Tv which is being used by the entire family at different time slots and each family member can keep their watch history separate even when staying logged in on the same device. The remaining 3 logins can be on a bedroom Tv and a couple of mobiles which may be used by individual family members.
