I like the article - it gives a clear rundown on the pros and cons of the simple built in diagramer, which I have found very handy.

The fact that the diagrams are tied to the actual system can be an advantage.

a) It encourages the use of referential integrity

b) There can be no "stale" diagrams

I always try to use referential integrity and set NOCHECK if the actual checking gets in the way.

The ref integrity constraints make for an instant diagram and also the relationships can be checked at some point by DBCC CHECKCONSTRAINTS. This is great for ETL processing where you may blow away the records in a lookup table and replace them later. At the end of all processing run DBCC CHECKCONSTRAINTS to see if any constraints are violated.