Sure, and so are the motherboard, screen, digitizer, etc. But that doesn't make it consumer-friendly. The battery in my phone is also user replaceable. A new battery costs almost $20, and requires me to pull the back cover off the phone with my fingernails. Whatever excuses a company makes for not offering that feature really just boils down to making money.
I'll take removing two screws to access the internals over having the entire thing fly apart when it's dropped on the ground any day. Do you remember removable batteries and cases from the early Nokia days? Even a minor jolt could interrupt the power supply and freeze the phone, so even if it didn't explode into four pieces, you still had to disassemble it and re-insert the battery.
Solid construction and mechanical fasteners are a feature. Servicing any part of an iPhone is not that hard; lack of serviceability is a myth.
Additionally, batteries are not the most commonly replaced part. So far my SE has had four screens and a lightning connector. I'll do the battery myself when I notice performance degrade, too.
