A project has mandatory and discretionary dependencies - 

• Eg: I want to build the swimming pool before I build the GYM, but I could do it the other way round, too

Only disadvante of discretionary dependency is that it can be mistaken for mandatory dependency if not articulated properly by the stakeholders. 

Discrectionary dependencies have to be added to plan and considered if possible

Thanks as where everyone talking about advantages only. You mentioned here the disadvantages too. As it gives us a sense of awareness and helps us to understand the real motive behind the case. Thumbs up and keep sharing on www.resumesservicesreviews.com/resumewritinggroup-com-review/ blog helpful material always.