That’s really not understanding of the true situation. There are plenty of Chinese who would call and tell Taiwan. They will know. And little planes like that are much easier for the anti-air missiles to hit. Just like the RoRos don’t have any defensive capability against even the smallest anti-ship missile.
Maybe the Chinese are planning to walk across the strait on the wreckage from all the sunken and downed craft.
Effectiveness of the tactic is one matter. That they’re trying it is another. They intend to take Taiwan. This is one secret program uncovered. How many others exist we aren’t aware of?