Thank you for your good answer, but the main Issue In Indonesia more than 50% user Bitcoin here using Indodax as wallet
time to studying more about bitcoin, I will try Mycelium
To make it simple, like any exchanges, Indodax has its own set of fees when it comes to deposit and withdraw. Maybe fixed or adjusting it depending on the current network traffic. It's a business after all. When using any exchanges, you are dealing with their own fees plus their own exchange rates. Not familiar about Indodax and their supported currency on their
"wallet" but you can take advantage of much cheaper withdrawal fees with the use of other coins
e.g XRP
(if supported).
However, using it as an own wallet might put you on risks since you don't hold your own funds here
"technically" that's why others suggested here to consider using a wallet that you really own and control
e.g Electrum.