Re: EA Play needed for purchased games?
It depends a bit on your own local situation and setup!
But in any case, you will need to pay for a subscription to somebody, one way or the other, to engage in the multiplayer online gameplay of the BF4 game. That is why it depends on what you may already have signed up with, to enable that. If that includes BF4 already or not.
Like Xbox, PlayStation and Ubisoft, Electronic Arts has its own games subscription service which provides access to its vast back catalogue of titles and more.
It is a paid service that is available across PlayStation, Xbox and Windows PC. However, owners of the latter two can also access it for free if they are Xbox Game Pass Ultimate members.
So what is EA Play:
Previously called "EA Access" on Xbox One and PS4, and Origin Access on PC, EA Play is a subscription service that offers like a "all-you-can-eat" access to Electronic Arts' own back catalogue of games, plus timed trials and early access for new games they release also. You also get 10 per cent off the purchase of new or future games.
It works slightly different on PC to console, with an additional EA Play Pro membership available for Windows PC owners that adds the ability to play games as they are released as part of an increased fee.
EA Play is available for one monthly fee on PS4, PS5, Xbox One, Xbox Series X/S and PC. It is available standalone or as part of Xbox Game Pass Ultimate at no extra cost.
As for myself, I pay for the Sony PSN subscription and paid for the full BF4 Premium Edition. So I use the PSN subscription for access to the online multi-gamer environment, and do therefore not need the EA Play on top. If you are playing many of the EA games, then that may be the better option for you, as you pay the fixed price but get access to play the full catalogue of all their many great games as you want !
Hope that helped to describe your options and why you may need the EA Play subscription.
(think when you bought the game, you got like 4 weeks of online gameplay offered, to try it out first)