You want a replaceable battery because once the battery wears out if the repair is expensive people will throw the used air buds. Used airbuds creates electronic waste ewaste on landfills.
Not all electronic recycling ä works well some non working electronics are shipped to Africa . The "recycler" takes the profit in the pocket. People have put airtags to track where such electronics to goods end up.
There is no proof that user-replaceable batteries meaningfully reduces e-waste. A lot of tech is upgraded due to obsolete CPUs, etc, not batteries. Plus, batteries last a long time now.
Also, landfills work really well. Most recycling doesn't work and pollutes more.
by the time the battery wears out on this one, the speakers are also busted anyway (infact it already is true for mine). So battery replacement isn't an issue for me, the device will be worthless by the time I am done with it.