The bowen website has some good images and it's a great idea for those that want to use a slide-in layout camper that sits lower than it would on a flatbed. Great that there are more and more options and choices out there!
In our case, the primary reasons that we'd consider changing to a HBE has to do with the layout of the camper itself.
For the winter, I'd actually prefer to have keep a pickup bed rather than have a flatbed. Camper is off the pickup for about 5 - 6 months out of the year (winter) and a bed would be much more useful in the winter than a flatbed. On a stock bed, I currently use a tri-fold bed cover to secure and protect my bulky wintertime recreational equipment (ice fishing gear/sled, skies, snowshows and any other long and/or snowy/wet equipment we don't want in the cab). That is part of our decision because losing the enclosed bed storage in the wintertime, when camper is off for the season, it a big factor. There are work arounds like putting side panels on a flatbed or using skyboxes or nets/tarps, but they are not as usable as a stock pickup with bed cover or a topper. That being the case, for our use case, the side entry door camper layout is much more convenient. We nearly always have a boat or enclosed trailer hooked up or a receiver rack with MTB or dirtbikes. We have a swing away hitch for the MTB, but dirtbikes are too heavy. Plus, hoping the side door allows less dust intrusion than the rear doors. Extensive gravel road travel and the vortex behind the vehicle lets in a fair bit of dust even with the door weather seals.
The HBE dinette is the biggest selling point for us. Very stable and large table surface and very spacious seating. The CAMP-X layout works for us, but we find the CAMP-HBE dinette more useable and comfortable. And we find the HBE living space a bit more comfortable for two people moving around compared to the CAMP-X galley/corridor layout. The indoor shower and toilet closet are also selling points for us. Time will tell if the HBE migrates to a more or less desirable camper for our needs.
Though the trail driving branch clearance would still be an issue if the CAMP-HBE continues to increase in height, as would the even less aerodynamic height, we would have a solution to still fit it in our shop. When we built our shop, which has 16' walls, we didn't have a use for a 14' RV door, so we installed a 9' door and opener for a small fraction of the cost of the 14' commercial-grade setup. We did, however, have the 14' height door header built and then a smaller and lower second header at 9'. That way, if we or future owners ever wanted the 14' door, it's a matter of cutting away the 9' header, siding/sheathing/studs and installing a 14' door and capable opener. That is the ace up my sleeve, but is an expense I'll have to take into consideration if we change to a pickup/camper combo that won't sneak through the current 9' garage door like our current CAMP-X/Fullsize pickup setup. It may come down to much more precise measurements because the current CAMP-HBE with an HD pickup setup is close and may not fit either as my estimates were roughly done. There is a very slim chance an even taller HBE will fit, but will just have to evaluate everything in a couple years because lots can change between now and then (OEV camper design, other available campers, our needs, etc.)