The three lines under the input where only one of them seem to matter at one time seems a little confusing.

Maybe just make it 1 line that replaces itself as you cycle through the options?

It looks like the units are still buttons, I think that's also confusing. Just have the one way to toggle the currency.

Also, this isn't something I see on wallets these days, but it would be cool to be able to choose a different currency eg. By long pressing for example... Sometimes I am abroad or just dealing with a foreigner and need to use dollars or euros instead of pounds for certain transactions.