You call do everything with the sqlite cli tool, but GUIs are very convenient to explore and play with the databases.

I have regularly used sqlitebrowser. You can even get create table statements corresponding to tables you have drafted with it, and you can copy-paste these statements in your code. Or build and test a sql statement incrementally, and paste it in your code when you are happy.

Or even to plain browse data, explore database from other tools, etc. There are a lot of occasions where such a tool can be convenient.