I suppose that it could be argued that weighing may not be as important on a trailer as it is on a motorhome since trailers will typically run the max tire pressure; that is not necessarily the case with a motorhome. 4-corner weighing (or at least front axle/rear axle) on a motorhome is important information to set tire pressures in order to provide the best overall ride, handling, tire wear, control, safety, etc. However, even on a trailer, it is important to verify you are not exceeding your trailer's GVWR and GAWR's or your tow vehicle's GCWR and GAWR. And tongue weight IS important to know; not in order to set up the WD hitch per se (that can usually be done by eye), but to verify trailer weight distribution and the added weight to the tow vehicle.
I find it funny to hear so many claim that they can accurately "guess" the weight of their belongings, their rig's overall weight, and their tongue weight. I would wager that most (if not all), if they were challenged to do so and then actually weighed their rig, would come up woefully short. And that doesn't even begin to address individual axle weights on the tow vehicle. Throw in a WD hitch, and any "guestimates" on your tow vehicle's overall and individual axle weights go right out the window.
When it is so easy and cheap to weigh your rig, and when the info gained can be so important, and when that info is impossible to accurately acquire any other way...I just have a hard time understanding the reluctance to do so, or the insistence that it is not important. Just my $.02
We don't stop playing because we grow old...We grow old because we stop playing!
2004 Itasca Sunrise M-30W
Carson enclosed ATV Trailer
-'85 ATC250R, '12 Husky TE310, '20 CanAm X3 X rs Turbo RR
Zieman Jetski Trailer
-'96 GTi, '96 Waveblaster II