Excerpt from "Strongholds" Section
It’s cool to have a place of your own. A headquarters, a base. A castle, a tower, a keep. It would be even better if your headquarters did something cool for you. Gave you some useful ability, preferably in combat, since that’s where a lot (not all!) of the game happens. It’s certainly where the life and death stuff happens. It’s also nice to have a reason to hoard money. Delving deep into dark dungeons promises three rewards: experience, magic items, and money. Experience is a self-evident good, as it makes your character level up and gain power. Magic items, likewise. They let you do cool things your character would never normally be able to do. Money, though? What are we supposed to do with it? At least one edition granted players easy access to creating magic items, a fine way to spend your money. A side effect of this is the assumed presence of shops in sufficiently large cities where you can buy magic items. But the modern edition makes the opposite assumption. Players during the 5E playtest said they wanted magic to be rare, and the dev team listened. Magic is rare and “magic shoppes” are not assumed in the base game. Strongholds and their upgrades, therefore, give you a good reason to save your money.