As a rule, Market accounts are used for fast trade execution, during which possible price changes are ignored. This enables a smooth and rapid trading process by allowing slippage. In most cases, the "Market" account type is recommended for trading.
On the other hand, Instant accounts allow traders to execute orders with high price accuracy, requiring the exact price to be available in the market. If the requested price is no longer available at the time of execution, the terminal will issue a "requote" — meaning it will request a new price from the server without completing the order. This approach ensures maximum price precision, usually at the cost of slower execution.