Even regular users of dApps often do not have an established mind models to determine the current value of Ether in an everyday currency (e.g. in € or $). Furthermore prices of transaction fees typically involve multiple decimal places which makes the conversion of price betweeen currencies more complex. Moreover only few (mostly experienced) users recognize the ether symbol.
Solution
Display all prices and transaction fees in a known currency, even if as a secondary display. Users thus have a better idea of the funds spent and do not need to perform conversions between currencies outside the application. The pattern can be used in a mobile or web application.