One reason not to practice certain techniques is that they are based on wrong view, and therefore not conducive to the goal.
I guess I don't really have a taste for other traditions within Buddhism as a whole. There's plenty within Theravada to get your teeth stuck into.
Taking on a practice without the accompanying framework I find can be quite jarring and doesn't seem to me to be the best of ideas. Getting inspiration is another matter but other traditions sometimes have a radically different understanding of the goal, so it doesn't really make sense to take too much from them.
Sometimes I'll try something new in meditation if I have been inspired by a particular teaching here or there, but I keep the main practice the same until I have really given it a good go. It's the only approach that makes sense to me.
I have seen some of your other threads and my advice is, little though it may be worth - don't let your meditation experiences guide your choice of meditation technique. If you practice a meditation and it doesn't go as planned and then you look to other traditions to explain the experience, seems the wrong approach to me. Work within one framework and it will be easier in the long run, I would think. Choose one, and interpret experiences accordingly. If you really think that you are more suited to one or the other then change, but I don't think it is a good idea to have two systems running at the same time.
"If beings knew, as I know, the results of giving & sharing, they would not eat without having given, nor would the stain of miserliness overcome their minds. Even if it were their last bite, their last mouthful, they would not eat without having shared."