round the wallet balance

To avoid currency exchange “jitter”.

Partially address #6707

js/about/preferences.js

@@ -1251,7 +1251,14 @@ class PaymentsTab extends ImmutableComponent {
     }
     if (this.props.ledgerData.get('btc') && typeof this.props.ledgerData.get('amount') === 'number') {
       const btcValue = this.props.ledgerData.get('btc') / this.props.ledgerData.get('amount')
-      return `${(balance / btcValue).toFixed(2)} ${currency}`
+      const fiatValue = (balance / btcValue).toFixed(2)
+      let roundedValue = Math.floor(fiatValue)
+      const diff = fiatValue - roundedValue
+
+      if (diff > 0.74) roundedValue += 0.75
+      else if (diff > 0.49) roundedValue += 0.50
+      else if (diff > 0.24) roundedValue += 0.25
+      return `${roundedValue.toFixed(2)} ${currency}`
     }
     return `${balance} BTC`
   }