there are some personal choices to make the decision. Storage space, versatility, cooking space, etc. that comes into play. That's some of my thoughts.
maybe your age, physical abilities may come into play. I sold an 18" wsm and opted for a 22" kettle and spent more on it for a temp controller as your having to play with vents moreso than a wsm, today I set the temp and let it go, no need to play with vents. Of course the well-versed smokers HAS more hands-on experience than I ever did which was not much at all smoking something twice a year.
for me it came down to setup and breakdown of the wsm as I didn't have space for a stationary wsm, maybe could have come up with adding wheels? But then again your still having to breakdown to clean the charcoal bowl and water pan(if used and it was heavy, at my age). Lost smoke cooking space but the kettle offered me less physical work at my age.
seeing some of you adding a 2nd grate on the kettle could get back a little space depending what's cooking
I must say, once you get used to eating smoked meats it gets addicting. The smell of smoking meat in the air and the remnants of it on my fingers just makes me wanting and going back for more. We have smoking joints on wheels in which a couple of years ago didn't exist here and everytime I catch the whiff of the smoking cook it makes me wanting, Addicting stuff
So sorry for the Ramblin