But Binance reduced withdrawal fee to 0.0002 BTC and bitcoin price dropped and the fee to be paid now is still less than $5. But this does not change the fact that Binance is not the only existing exchange, there are some that charge far more higher. You can check the lists of exchanges and the amount of bitcoin they charge as fee, also in USD:
https://withdrawalfees.com/coins/bitcoin
With $250 at the time bitcoin was around $7000, I make use of Changelley as this party on Coinomi, it can charge $7 or more. I noticed as the amiunt to exchange increased, the fee also increases.
Coinomi is not recommended because it is close source wallet, also instant exchanges can freeze your coins. I used it when I knew little about privacy and having full control over owns coin.
If you are withdrawimg large amount, it is better to make use of Binance directly. Binance just started BTC pair free exchange but not on many other exchange which may charge at least 0.1% as fee. The fee that would be deducted for that on other exchanges, especially for high amount of bitcoin would be higher and also converting it back to bitcoin on instant exchange also would be higher in fee. Withdrawing directly on Binance would be better than first sending it to instant exchange.