Honestly, let SE make as much money as they can.

[Shneibel]

But you probably will. Even though it's still considered optional.

There are ppl who spend 1k-2k$ just for a mount or a vanity clothes in F2p and there are ppl who farm their money ingame and buy those items from other player.

In the end it is optional for most f2p and so is the retainer service in here too.