Digital filter as physical device
Digital Filters as dedicated pieces of hardware are quite rate these days. Most filtering just happens on general purpose CPUs such as ARM core and may be partially accelerated by specific instruction sets or co-processor (e.g. NEON). Your smart phone or your laptop do a lot of digital filtering every day.
Dedicated filter hardware is typically part of a special purpose SOC (system on a chip) that's design for a specific  application like a cable modem or ANC processor). The filter  implementations are optimized for the specific application and &quot;configurable&quot;.