This is just my view..
Other people I know that bought 17" were someone who has assistant to carry it around. They need real-estate screen bla2.. someone who is a pro photog / videographer
It just doesn't make sense. If you always carry your macbook around, you should buy something lighter like 13". If you like to have something that has better performance and maybe bring it 2 times a week, then go for 15" macbook pro 17" is just too big for ordinary users.
For me, desktop replacement is working laptop for travelling. You bring the laptop and after arriving at your destination, you put the laptop on the work table all day long. That's desktop replacement. If you always carry it around that heavy machine all day long, I'm afraid you will get 'shoulder-replacement' 😀 just kidding..
It is personal preference though..