Here is 6 days of my line, it isn't great, it has been better, but I have no issues with VOIP.
A little bit of "smoke" is ok. From 3 spots you're looking for a daily rise in latency or a simultaneous chunk of badness and there isn't anything on your graphs except for a small amount of irregular noise.
If there are problems like tiny outages cutting off calls then they're too short for smokeping to see, it only does a test every 20 minutes which is good for picking up daily patterns or much larger issues only.