You also have the ability to remove your built structures for 10 minutes using a normal hammer, so if you make a mistake (even if your structures are upgraded) you can easily fix the mistake using a normal hammer. For the most part you won't need a Salvaged hammer until you want to make changes to your existing base design, or move items around that you normally can't pick up using a normal hammer (such as Workbenches).
After 10 minutes, a Salvaged hammer will be required unless you want to use a Jackhammer or Explosives to remove structures. The Salvaged hammer is a great item to use for this purpose, and as it doesn't have much of a use or purpose in vanilla rust, it only costs 75 scrap to research, and only costs 1 metal pipe (these are easy to find) and 50 metal fragments to craft. It's understandable that they can be difficult to find while looting, but as Granny previously stated, you can find them commonly being sold at other players' vending machines.
Although perhaps Death could add Salvaged hammers to the RustEZ store for purchase as an extra way to obtain one, especially for use during the beginning of a server wipe.