Arrays vs databases

[Matt Maier]

I already know how to use Livecode and I think I can do everything I need
using arrays.

According to this lesson, I can store an array as a custom property of a
stack which can be saved and loaded.
http://lessons.livecode.com/m/4071/l/17375-how-do-i-save-custom-properties-in-a-standalone-application

Something I've done myself already is to either save the array as JSON in a
text file or just as a binary with encode.

So, in the most naive sense, it looks like I can have a key-value store
without installing and learning anything new. But databases have extra
functionality to deal with stuff like multiple simultaneous users, data
integrity, and performance optimization.

Can I just setup an instance of Livecode to act like an in-memory,
key-value database? Maybe have a standalone stack act as the controller and
have it mirror it's state in a separate stack that can be saved and loaded.

I don't know enough about database design to frame the tradeoffs. Can
someone who groks both Livecode and databases comment on this idea?