Normally every project needs custom values saved on products or another entities. Shopware does offer by default Custom fields. It looks nice, but it can produce very fast issues.
Before we start: This is my opinion
Let’s start with a simple Pro Contra list.
Pro Can be easily created in the Administration / Code. Can define field types, labels etc and Shopware does the rendering in Administration for me Loaded by default on the entities Custom Fields are schema less. You can save anything in it Contra Custom Fields are schema less. You can save anything in it They are saved as JSON Hard to modify using SQL Cannot have associations Slow on SQL Filtering, Aggregation Loaded by default on the entities Support between MySQL and MariaDB differs and Performance Cannot have Flags. All fields are public using Sales-Channel / Store-API Cause it does not have a Schema they will be indexed as dynamic in Elasticsearch. This brings lot of other problems You don’t have a control is it translatable or not Fields values cannot be easy deleted on all entities. You need to modify each entry. The most problems are introduced cause of the usage of an JSON field. In SQL the accessed fields needs to be extracted. This takes some time of course. On a bigger shop using many products this could leak to performance issues in the listing when it’s used inside a product filter.
...