My players were coming up on a point where they would be back at their homebase and were talking about trying to find various magic items, wanting to craft certain equipment and change weapons up a little and I couldn't construct that on my own as a new DM and the in-built crafting system in the DMG is extremely lackluster.
I heard about this from the crew at The Hook & Chance Podcast and it sounded like a perfect fit for what my players wanted without balance issues without a ton of magic items dropped in, and a actual reason to get gold. Turns out that iy absolutely was EXACTLY what I needed in a very well written format that looks amazing and has some solid mechanics for how it all fits into the game seamlessly.
If you are a DM with a party interested in giving basic weapons an edge (pun intended) and not wanting to flood magic items at them for reward this is your book. If you are a player looking to keep a weapon that was given as an heirloom or symbolic reward and make it viable for higher levels, this is your book, (and of course talk to your DM outside of a session about implementing it first).