Yes, they do make the ride more pleasant, and take shock away from wrists, shoulders, backs............. Yes, the lockouts do work well for when you are climbing or are on a really smooth road. Yes, they may make it possible to keep riding longer.
No they are not all junk, and maintenance has been zero for the last 5 years. No, it doesn't wiggle, shake rattle or roll. No, I don't notice the weight, as my bike is pretty utilitarian almost always with rack, fenders, tail trunk, panniers, lights, pump, various tools and locks, etc. It ain't a lightweight. But it will do almost anything I ask of it.
If you want it, don't be afraid of it. Almost all name brands are really decent trekking suspension forks. I ride 6,000 - 9,000 miles per year.