Open Barrel splice vs y splitter

Is there a particular reason to use a open barrel crimp instead of a deutsch y-splitter?

http://www.deutschconnector.com/products/deutsch_connectors/deutsch_dt_series_connectors/deutsch_dt_3-way_connectors/DT04-3P-P007-Assy/

Those are for completely different purposes. We can make dozens of splices inside an harness, and would use open or closed barrel crimps to accomplish this. I have no idea what that external splitter would be used for, perhaps something with lighting on the car. It's unlikely we would ever use anything like that on the engine harness, we would just split the harness and have two connectors, located in the perfect position.

As David has mentioned, its about space. An open barrel splice is much, much smaller than the Y-connector. While, electrically I'm sure you could make the Y-connectors work, you'd have to build many, many individual harnesses and things would get pretty bulky pretty quickly :-).

Those Y's are great for quick CAN expansion in conjunction with Deutsch's terminating resistors but as mentioned I'd never use them in a harness.