Hi @simonthesorcerer,
Great question! If you switch to an SQLite database this will result in a new database without the content you had existing on your previous site, which used a MySQL database. You can however switch back to the MySQL database that contains your pages/post data at any time, by disabling the SQLite module.
You’ll find out more on this below: https://make.www.ads-software.com/core/2022/09/12/lets-make-wordpress-officially-support-sqlite/
I’ll also pass on your comments regarding the wording. You can submit an enhancement request on the plugins GitHub repository if you wish.
Let me know if you have any further questions on this.