Iphone battery is already pretty close to replaceable by this law. You need a common tool to get in (trident screwdriver is available in most DIY shops), then glue tabs can be pried by hand. Doable for layman? Well, some people are afraid of opening up a device in any way. How do we (or, rather, lawyers) draw a line?
There should be no reason to use glue for batteries. Unnecessary hazard that can easily lead to house fire if you have to use force of a thermal source to remove the glue.