The sight glass goes into the bells and whistles category. It’s pretty much a one shot thing that can be done with a dowel with number on it. The thermometer is something I wouldn’t be without for both chilling and approaching boil temperature. I use the lid to get to boiling quicker, but use that time to start clean up. It's nice to be able to glance over and see how close it's getting without taking the lid off. Or having the mess of a boil over.
Personal taste is one thing, but to be arrogant about yours is what makes you an a-hole. Don't be an a-hole with personal taste.
. . .This has been a PSA from your local Klubb.