yes it is very much applicable but it's not necessarily the biceps. you could instead go for the inner part of the arm, between the biceps and triceps, where you'll touch directly the humerus, along with the brachial artery and nerve. I have been hit there lightly a few times and mate, as if it wasn't bad enough for the arm to "die", it hurts so much, and it's a very different kind of pain. horrible.
the same goes for the armpit (right there in the joint with the arm) and upper ribs. (words cannot describe how mindbreaking the pain of getting a punch or kick in the armpit is)
what you seem to be pointing out is that reflex, similar to a tap on the knee when the quadriceps is relaxed. plausible but in a fight, for sport or self-defence, the body naturally stiffens.
that's why such techniques are viable but unlikely. testing on yourself and then on a partner is good, but the real proof of concept is pressure testing, that is, trying to apply a move while your partner is resisting and the least effort they need to make to cancel your technique, the less likely it'll be to apply in an actual situation (again, sports or self-defence)
another option is to knife hand it, just to give that short unbalance and, since your hand is open, grab the muscle or the skin to follow up by a body strike, elbow to the sternum for example. (I thoroughly recommend training grip and pinch strength for any martial artist. a good start is push-ups but holding a towel thrown over the bar). the point of aim would be in the upper part of the biceps, next to the tendons attaching it to the bone, almost shoulders and if you're a featherweight like me, it feels like hitting pure bone. you'll see that part being targeted a lot in chamber blocks, called sen-no-sen in karatê, where you act before your opponent, normally impeding them to either strike or move around
so long text short: if you want to cause pain and play puppets, nah yea mate, sure. if you want to go ninja pressure point, yea nah mate, nope.
all this is from personal experience and studying/watching both the technique and the
human morpho physiology. and I hope this is understandable enough to convey the message. sometimes my English simply fails me