Your experience will vary, but perhaps: 4-5 bars => 98% likelihood that everything is great. 1-2 bars => 20% quite good, 50% pretty decent, 20% quite bad, 7%

Your experience will vary, but perhaps: 4-5 bars => 98% likelihood that everything is great. 1-2 bars => 20% quite good, 50% pretty decent, 20% quite bad, 7% bad, 3% no service. How is something like that meaningless? That is immensely useful. You can also reason about it depending on the context. Downtown but inside a bar in a cellar? Or out in the country far from civilization? That it isn't perfect doesn't make it meaningless.