The waterfall method is for leadership in the C-suite. Agile is for the product developers on the creative edge.
Agile has become the dominant product development philosophy and approach to business solutions.
Agile can be a daily discipline for continuous delivery or it can become a never-ending excuse for disorganization and unaccountability.
At best, Agile brings breakthrough intensity and real-time ground-truth clarity. Agile can avoid the self-sabotaging anti-pattern of indecision today fed with dreams of tomorrow's impossible perfections.
At worst, Agile is an excuse for busy work and forever poor quality.
The reality is that agile is the smaller daily or weekly cycle that fits within monthly, quarterly, or yearly waterfall project plans.
Waterfall project plans for product and service development are important for large-scale enterprise or departmental endeavors. Executive and management want to see waterfall plans.
In summary: the Waterfall method is for leadership in the C-suite. Agile is for the product developers on the creative edge.