By adding this change to the bottom of the dump.sql file it will “re-add” your edit after the clear and rebuild each reset. So just changing the database directly will not work as it will get cleared and rebuilt by the dump.sql.
As to why we put this in the dump.sql file is because that file it setup to run on every server reset and the first thing it does is dump/delete several tables one being the objects_types table we plan to edit. The recommended method of updating the database is to use an SQL UPDATE with only the columns you want to update in it. Note: basilmod if setup properly will automatically generate the objects_types.xml for clients based on the current objects_types database table. dump.sql on the Server and objects_types.xml for your clients side if you don’t use basilmod. To increase the max storage/container size of objects and items you have to edit two files.