Unfortunately you are mistaken. They can‘t just place it in there loosely. It needs to be mounted in some way. Right now, repair guides glue the replacement battery back into place as well so it‘s actually not something you should skip. The new mounting system can very well result in a smaller battery size.
It sits perfectly flush in its compartment and then has a plate pressing against the back when closed back up. It really doesn’t need the adhesive. If you ever had to send it to Nintendo, tho, it not having the glue would be a clear indicator you opened it up and voided the warranty.
Unfortunately you are mistaken. They can‘t just place it in there loosely. It needs to be mounted in some way. Right now, repair guides glue the replacement battery back into place as well so it‘s actually not something you should skip. The new mounting system can very well result in a smaller battery size.
It sits perfectly flush in its compartment and then has a plate pressing against the back when closed back up. It really doesn’t need the adhesive. If you ever had to send it to Nintendo, tho, it not having the glue would be a clear indicator you opened it up and voided the warranty.