Numeric columns provide a few options. If you are using the field to keep dollar amounts this is the perfect field type. If there is any concern that you will need characters of any kind then use a text field rather than numeric which will only accept numbers.
The Currency column type will include the currency symbol and allows you to select the currency type by country via a drop-down menu.
Currency Field Validation
This feature was developed as a customer informed us that currency columns were not being entered correctly by users but there was no notification to them and therefore the fields continued being empty even though the user thought they had entered the value.
There is nothing to do to get this feature but update after February 2017. Flex input forms will not allow currency columns to input any character other than valid numbers/commas/decimal points.
This is now the default behavior for all currency columns in all lists within Flex.