You are right, I also was not aware of this feature until I got the notification and upon checking I saw we now have more options as well, for example before we only have like 2 options, tracking username, and other one is not coming to my mind now, but now we can also track topics and can get karma notifications as well. I wonder if we can get negative karma notifications as well or not.
PXZ is doing great, although we have another source to know about karma and mentions which is made by bitmover but this bot of PXZ is more helpful, everyone has their own taste in using tools, its just 2nd month and we get what we needed, and with time more developments will be made, more toll will be seen by us that will make our lives more easy.