In our days more common are phones with batteries that are glued and screwed into the inside. You can take it out only with special tools.
There are a few reasons why smartphones with removable batteries have lost their touch. One of them is that this new non-removable battery isn’t only for your convenience. The lifespan of an average smartphone battery is about 24 months. After that, it starts losing its capacity. And your service provider will be happy to sell you a new phone!