The benefit of digital feedback is that it can easily provide rapid-cycle feedback: students and teachers can respond quickly to each other. The timeliness of feedback is what makes it such a powerful learning tool.
Effect Size .73 (Hattie Teaching Effects, 2009)
Clearly, not all formative assessment tools are digital. Here is a list of 60 'unplugged' formative assessment tools/strategies that could be leveraged for in-person or digital learning compiled by Orange County Public Schools.