Why there are both counters and gauges in Prometheus if gauges can act as counters?

Question

When deciding between Counter and Gauge, Prometheus documentation states that

To pick between counter and gauge, there is a simp

Answer 1

For counters you care about how fast it is increasing, whereas for gauges you care about the actual value. While there can be gauges that (in theory) only go up, that doesn't make them counters.