Just like the HTC 10 and Google Pixel: It's a solid phone but there's really nothing spectacular about it.
I personally don't understand why some people view removable batteries as a must. I think it's better to carry around a rechargeable external battery pack than an unprotected battery, especially since you probably won't be able to charge that battery outside of the phone. This isn't a camera which has some battery charger for the removable battery.
Also just makes for another part of the phone to fall off if you happen to drop it (remember the Galaxy S5 and older days).
I disagree. I could think a few uses where a removable battery is the better choice, especially in portability. I'm not sure for the V20, but the last G4 that my sister had provided a free battery, a charger for that extra battery and also a case to carry that battery around. All in a smaller footprint. And with using a removable battery, you don't have to worry about a cable (although it's equally annoying you'd have to shutdown the device to swap the battery, but I digress).
Also, with removable battery = removable back (minus the G5) = "safer"phone after a drop. Plus, if that breaks or anything, just swap with a new one. Permanent battery with a permanent back after a drop will have permanent scratch or damage. Not much of a problem if you have a case on, but quite a lot people don't put any case on. Go figure.
Oh and lastly, when a battery starts to bulge (after a year or two though), just swap it out. No need to send for repairs with exorbitant pricing and long waiting times.
edit : https://www.amazon.com/LG-Battery-Charging-BCK-5200-Charger/dp/B01M5C23SV
Here's the V20's battery kit. Pretty pricey though. Hoping that LG does their usually "free battery kit with every purchase of LG phone".