Why need to aggregate a double IF-statement for variable

[Applicable88]

Hello,

I'm using a variable in a button to switch a dynamic table.

I have Order Id's which have Status K and others have the Status V:

er	Status	Startdate
111111	K	18.06.2020
222222	V	19.06.2020
333333	V	22.06.2020
444444	K	24.06.2020

The formula for the dimension startdate.autocalendar.date is like following: 

if(If(vVariable='0',count({<Status={"K"}>]Orders),
count({<Status={"V"}>]Orders)))>0,
StartingDate.autocalendar.date))

So practically it means if the button switch is set to variable '0', count orders with K otherwise count orders with V and in either option, the value needs to be greater than 0, then it should return me the dimension startingDate.  I'm wondering why I get no returns.

Only with aggr I get the switch between these working:

aggr(if(If(vVariable='0',count(distinct Orders),
count(distinct Orders2))>0,
StartingDate.autocalendar.date)),StartingDate.autocalendar.date)

Can someone explain to me why I need to aggr and put another StartingDate to the end? For me the first function was fine, its practically the same as the following single if-statement  function simplified, just that it has no variable and no Status K and V filter:

if(Order>0,StartingDate,0)   

Of course this one has no Status K,V filter and no variables. But it returns me every StartingDate for EVERY row, as long there is a OrderId given.

Thanks in advance.