Any form of SQL is only as fast as you make it. Data stored in SQLite tables is not stored in memory, so it takes longer to get that data. Depending on your scenario, you may want to cache this information in player variables. Some reasons for using SQLite for data storage are easy offline access, easy backup, organization, and easy querying/retrieving that data.
Ultimately if you decide to use SQLite, index it well and make sure you know how to use indexes.
This page in particular may be helpful. Read section 1.1 carefully so you understand how the left-most column in indexes works; if you don't, your indexes won't do ****.