Most US Government communications require Fax.
As a Builder, I always include a Fax Modem Card in my Builds.
The Best Modems are what's known as Hardware Modems but they require a PCI Slot.
Since most new motherboards only have PCIe Slots, then a Software Modem like this is what's needed.
A Fax Modem can be used at the same time as DSL, just be sure to use a Filter Jack.
Your Bank will always be glad to Fax for you if your equipment does not support Fax.