Stonger aftermarket bumpers have always been worth it to me. A lot is based on how I typically use my vehicles which is some mild overland/camping with a mixture of moderate-difficult rockcrawling. If it was purely overland travel then my approach might be different but since i play in the rocks too it means it's worth it to have a little extra beef to keep things protected.
For me the necessary elements of good bumpers are:
1) Protection from rocks and other trail obstacles, but still maintain excellent approach and departure angles as much as possible.
2) some improved protection from animal strikes (but that's lower on list since most of the places I wheel rarely encounter animals)
3) winch mounting for the front bumper, as well as recovey points at the front and the rear.
4) location for things like spare tire, hilift, fuel. (I don't like any of those things taking up space inside the truck and rarely can a fit a big enough spare tire in a factory location)
5) Aesthetics. Maybe because I'm an artist for my day job I can't go purely for function when I consider bumpers or anything else on my trucks for that matter. It still needs to meet my functional requirements but I like it to look well designed. Sometimes that's a difficult balance and in the end function will always win out but as much as possible I try to make it look good too.
So from my experience that includes LOTS of rock bashing, a couple different deer that have moved on to a better place, and just the things you figure out over time that make life on trails more convenient I've settled with my current setup on my Tacoma (which happens to be a very similar setup to what I've had on my FJ40 and my FZJ80.
For the front I chose a TrailGear low profile bumper with light bar. This is the first tube style bumper Ive had. Aesthetically tube is not for everyone. But for me this bumper has been great and has met all my requirements. I particularly like the high clearance it offers and it has given excellent protection so far.
For the rear bumper there wasn't anything on the market that met all of what I wanted without a ridiculous pricetag. So I built my own. It happened in phases but I finally completed it over the weekend and gotta say I'm happy with the results.
Started out as a stronger than stock simple bumper that improved clearance, included a reciever hitch so I could tow my trailer and some lower bedside protection.
it still needed a tire carrier so I could carry a fullsize spare that didn't take up bed space. So I built that and added a place for my hilift jack.
Then I still needed a place for extra fuel/water, and some rear aux lighting. I finally finished that part of it this past weekend with a second swingout. It now has what I need.
Both of these bumpers have taken some solid abuse. Without question the factory bumpers would have been destroyed by now and I'm sure there would be other damage to the truck as a result. So from my perspective in answer to the original question of the thread, heavy duty bumpers are a practical necessity with nothing superfluous about it.