Forum:Why cant you use your ps4 account for the pc

i have dc unaverse online for my ps4 an paid the mothly $14.99 for this moth but i have to have a nother account to play it on my pc it would be nice if you could be able to use your ps4 account so you dont have to pay extra just to get the new addons. just to let any 1 know what im saying on my ps4 im lerch3685 an for my pc im bloodhaven y do we have to pay more to just play on pc if we feel like it when you allready paid for on a nother