A balance on the site is fine

What a parked balance actually is

Money you have handed to a platform and not committed to anything. It is not in escrow, because escrow governs orders. It is not protected by the multisig arrangement, because nothing has been contracted. It is simply held, on your behalf, by a party you cannot identify and have no recourse against.

Every protection described anywhere in this register attaches to an order. A balance has no order attached, which means it has nothing attached.

What can happen to it

• A platform ending. Nobody predicts this, and every market that ended badly looked healthy immediately before.
• Your account being lost. A compromised or unrecoverable account takes the balance with it, and the account is far more likely to fail than the platform.
• An extended outage. Not a loss, and it is a period where you cannot reach your own money and have no way to find out when you will.
• Your own attention lapsing. The quiet one. Money left somewhere for six months belongs to somebody who has stopped watching.

Why people do it anyway

Three reasons, all understandable and none good. Funding is the least pleasant step, so people do it once and generously to avoid repeating it. Fees make a single larger movement look cheaper than several small ones, which is true and irrelevant next to the risk. And a balance feels like it is somewhere rather than nowhere, which is a feeling rather than a fact about custody.

The rule

Fund what you intend to spend soon. Not what you might spend eventually, not a round number, not a buffer. If an order is not going to be placed within a short window, the money should not be there.

The fee argument is worth answering directly, because it is the one people make. A network fee on Monero is a fraction of a cent. The convenience of a parked balance is bought with an unlimited downside and saves an amount too small to name. That is not a close call, and it is the one piece of advice in this register that costs nothing to follow.