Signal strength can help estimate link conditions, but it is not the whole quality story. A strong desired signal can still be difficult to decode in a noisy or interfering environment. Strength and intelligibility answer different questions.
RF introduces many concepts at once: frequency, modulation, antennas, packets, routing, and applications. A layer map helps separate physical-signal questions from protocol and application questions.
A sensor message may contain only a few bytes, but many sensors can share the same radio medium. The important question is not only how much data exists, but how long each transmission occupies that shared medium.
A board antenna gives clues about expected behavior, but in a real product the surrounding objects become part of the system. The enclosure, cables, metal parts, and device placement can all change the result. An open-board test is not a guarantee for the finished enclosure.