> there are no reasons why a phone needs so many glued parts There are numerous reasons (some very good reasons) why adhesives are used in smartphone assembly.

> there are no reasons why a phone needs so many glued parts There are numerous reasons (some very good reasons) why adhesives are used in smartphone assembly. Sometimes these reasons can sometimes come into conflict with repairability, but that doesn't render their usage completely devoid of any valid reason. For example, many uses of adhesive are to improve water resistance. And improved water resistance reduces the likelihood of a product needing repair, which is equally virtuous (in my opinion) as repairability.