In every discord bot you will always need a database to store your member's data such as XP, economy, tickets etc...
JSON file
In the bot builder it is considered a database, but in reality a JSON file isn't a database, in this case it "acts" like one.
PROS:
Easy to set up and to use
CONS:
Not ideal for storing a lot of data.
Larger the file size is, the more it will take to process data.
You will probably not experience most of the cons since there is the need of a very very large dataset for these problems to occur.
Still, if you have a big server we recommend to use the MongoDB database.
MongoDB
MongoDB is a very popular database and can handle a lot of data without impacing its performance.
PROS:
CONS:
Harder to set up if not familiar
You can get a free MongoDB database in minutes with MongoDB Atlas (https://www.mongodb.com/atlas/database)