I use both: I make a point of using cash where I can, and I tend to avoid places which say "we are cashless".
If we as a society go any more cashless than we already are, this may well bite very hard one day. We've already seen what can happen if big computer networks go down for a day. And yes, I am very concerned about every transaction being traceable. Remember the madness of "you must not buy Easter eggs because doing so would kill granny"? Under a completely cashless society, especially if it develops into one that tracks not only the amount spent, but what it is spent on, which would be the next step, enforcement of such draconian rules could become a reality. Slippery slope. I bet a Cobra meeting or two contained the line "if only we were a truly cashless society".
I visited a small tourist attraction on New Year's Day, which had big signs saying "we are cashless": but the staff were looking sheepish, saying "actually, we can only take cash today, our internet is down". I bet they lost a lot of money that day.
Yes, cash can be stolen, and keeping vast amounts of cash under your mattress is ill-advised. But I don't think it should be abolished completely, and I intend to keep using it, so that the statistics show that people still use it.