What is the use of upgrading high lvl buildings

Barrier Spikes - No defence bonus while also requiring Treated Wood? Compound Door - requesting engines that require fuel for crafting while no defence bonus. And so on...

Ok, Now without frustration and more productive. Guess the system can be extended and made more to looks like progression. 1. Stop adding morale based points for defence after current cap is reached. Instead add %ressistance to all buildings since the means of destruction grow exponentially at the end of the game. (Applied to defence buildings) 2. Either/Or: Increase range for towers, Increase suppression resistance for baricades. 3. Add return damage to Spike and Wire barriers (Perhaps also Wire traps). (Damage avoidable only if wearing Trap Tools and trying to destroy them) 4. Increase size of Beds, add Romance option. (small morale boost? Or better stats while inside same session?) 5. Add Sapper as class (in PVP used as sabotage unit (against water and food ressources). Either by contaminating which can be reversed with medic and antibiotics. Either by adding rodents and bugs to Compound inside area (Decrease Comfort, Add Sick as Status of Injury). In PVE he can trow concoctions that can be created in Gear Bench (similar to Grenades) .

I mostly only upgrade these things for the Security/Morale bonus. I would not suggest increasing the range from the watchtower, because you can already cover the whole map with the right equipment.

I was talking about lvl 8 upgrade that provides no morale or defence bonus. If you can cover the map as an defender you can also get that as an attacker. That being said since in defence is AI playing from a standing position and no grenades used I consider a small upgrade to range would be a nice to have.