I think the hidden-condition of an object will be checked with each interaction on the sheet and will be therefore need more performance then if all these objects would be on a different sheet. But if there are not many objects and/or the conditions are heavily complex by a larger dataset it should be not very significantely.
Robert, there is no huge performance impact between Hidden vs different tab other than if you write complex expression in object Hide/Show condition.
In my opinion, different tab have better edge in the performance because we are simply activate the sheet with out any complex expression. But different tab approach take little bit development time because we have to copy all filters (LB) , buttons and other object to make consistent on UI.
The other option you may consider the container object.
If we have any performance issues, conditional the sheets based on QVUser with Section Access.
In this way hiding the sheets will give you better performance.
In this way, the sheet will be dropped from the memory and load only the user sheet trying to login...
I would also suggest to refer Manish post mentioned above