Why exactly would people change batteries that don't need to be changed? Phones do have battery health indicators, and buying one costs money. There's no logical reason to change one, until they have degraded significantly. The only difference is that now you can change it more easily yourself, rather than having someone else do it for money, which they will happily do regardless of battery health.

When combined with requirement for longer support with updates, this change in legislation will help creating a healthy second-hand market for more devices. Cheap, non-serviceable Android phones that get updates and are used only for a year or two are the real source of waste, we need a proper second-hand marker for those similar to expensive Apple devices.