It's not clear to me if they're totally interchangeable.

to my understanding they can work in the same way, using DECIMAL OR NUMERIC is the same ..in short DECIMAL (7,2) is the same as NUMERIC (7.2)

Hi Sylvio! Thanks for reaching out. There is one notable difference between NUMERIC and DECIMAL in standard SQL. The NUMERIC data type is strict; it enforces the exact precision and scale that you have specified. This is in stark contrast to DECIMAL, which allows more numbers than the stated precision. Hope this helps. Best, Tsvetelin