It takes more than 1 minute. You have to stop what you are doing, take off your phone from the case, turn it off, open the back, find the tiny battery somewhere in your bag, change the battery, put the back cover and put your phone back in the case, turn it on, wait for it to boot up.
and that is if you remember to actually double charge that extra battery, that can only be charge through your phone.
With an external battery pack, you just plug it in, done. To recharge it, just use any charger.
Heck, even Google stopped bothering with a removable battery on their design language.
Dramatic much? You're describing a situation where someone looks at their phone and it's at 1%, and they need to make that emergency call and are struggling to swap batteries.
In reality, you look at your phone throughout the day and you may find that before lunch you're at 50%, or before dinner you are at 25%, point being you know when your battery is almost dead. So with a second battery you wait until you are taking a break, whether it be a bathroom break, lunch break, or waiting for your friend, and you take the battery out of your pocket to swap them. Sure if you have an Otterbox it's a pain, but many don't use cases, or use those thin silicon cases that slide right off. You don't need to power it down, you just pop the back off, swap them, turn it back on, and put it back in your pocket. When you go to use it again it's at 100%.
Now compare that to your scenario. You look at your phone throughout the day, see it hit 50%, then 25%, and you need to think about charging it back up. Now instead of finding 2 minutes in your day to be without your phone, you need to either throw your phone in your backpack connected to the charger, or have a clunky battery charging your phone in your pocket, making it virtually impossibly to use while moving until it's done charging. Then you have the potential problem where you thought you could be without it for an hour, but after 5 minutes something comes up and you need to leave.
TL;DR - A removable battery gives you the choice to swap them in 2 minutes and be right back at 100%, or use a portable charger. Without this, you have to use the charger and keep your phone connected for an hour or two to get back to 100%.
Removable battery is a pathetic excuse. Also the first thing that happens to a phone with a removable battery when it falls is the battery cover pops out. Nowadays with fast charging and great battery life, there is no need. Can't remember ever swapping or wanting to swap batteries in the past 15 years of using phone.
Sounds like you haven't used one in years. My original Moto Droid and Thunderbolt did this and it annoyed me, but everything since then did not fly apart when it was dropped. You'd never know it was removable as it's just as secure as those that aren't. Fast charging is great (too bad Apple doesn't have this), but doesn't help you if you aren't near a charger.
Besides, after 6 months, 1 year, 2 years, battery life degrades. Instead of sending it in for repair or following a DIY guide, you can buy a new battery and swap it yourself in a minute.