What does a card really do?
- It helps clearly group information
- It helps group information with relevant tasks
- It can help to show quantity of information according to need
- It can help show other aspects of information normally not seen upfront
There are several ways to group information as per the need of the users and brand. Graphic designers and user experience designers have been grouping information as a part of their job.
In the recent times, a lot of people needed to group and categorise information. However, without the knowledge of Gestalt's Laws and training in graphic design, it is a guessing game for anyone. At that time, card based UIs came to rescue - they did the job perfectly - and looked good too!
So, if you and your designers have zero training in graphic design, and you have an information heavy website/application, card based UIs can be good.
And, one word of caution, group information that makes sense to users together (even if it comes from different database tables). Do not naturally group information that are columns in the same table in the database!