What do you think the major practical downsides are? Maybe you are not aware of how many things perfectly work or how easy some workaround are, so I am wondering.
The average person uses Chrome with no ad-blocker on and has never opened a terminal emulator. HN wildly sways to a tech-aware audience. I think most people would read the simple instructions provided by the author and immediately be overwhelmed and confused - "what's a bootloader, why do I need to care about unlocking it, is this going to break my phone?!"