Count rows of a table
Just some things that jump out at me:



You don't reset OnError

Huge red flag right there. If you're going to change OnError Goto you should immediately write the corresponding lines to set it back to normal. 

Specifically: (Square brackets for emphasis)

    On Error GoTo CurrencyTradesEmpty
    CountCurrencyTrades = tblCurrencyTrades.DataBodyRange.Rows.Count
    [On Error Goto 0] 

CleanExit:

    Exit Function

CurrencyTradesEmpty:
    [On Error Goto 0] 
    CountCurrencyTrades = 0
    Resume CleanExit




Your function has too many responsibilities

Single Responsibility Principle. Your function has a hardcoded worksheet, hardcoded listObject and then handles the counting of said object. I would have the function take a ListObject as an argument and let another function handle the retrieval of said objects. Like so:

    Option Explicit

    Public Function GetCurrencyTradesCount() As Long

        Dim sheetCurrencyTable As Worksheet
        Set sheetCurrencyTable = Worksheets("CurrencyTable")

        Dim tblCurrencyTrades As ListObject
        Set tblCurrencyTrades = sheetCurrencyTable.ListObjects("CurrencyQuery")

        GetCurrencyTradesCount = CountListRows(tblCurrencyTrades)

    End Function

    Private Function CountListRows(ByRef targetList As ListObject) As Long
        '/ On Error (I.E. empty list), returns 0

        On Error GoTo CleanFail
        CountListRows = targetList.DataBodyRange.Rows.Count
        On Error GoTo 0

CleanExit:
        Exit Function

CleanFail:
        On Error GoTo 0
        CountListRows = 0
        Resume CleanExit

    End Function


Scoping

Your function is implicitly public. You should explicitly set a Public or Private scope for it.



Integer

Is officially deprecated. The compiler will silently convert all Integers to Longs, so just use Long instead.



Error Handling  

Do you really want your function to return 0 for all errors? What if it's given an empty object reference? I would rename your label to CleanFail: and think about what other failure scenarios it might want to deal with.