Are adjustable dumbbells worth it compared to a full rack?

For home gyms, absolutely. A pair of adjustable dumbbells replaces 15 to 20 individual dumbbells, saving a lot of money and significant floor space. A full fixed dumbbell set covering 5 to 50 lbs is expensive and takes up an entire rack. Adjustable dumbbells covering the same range cost far less and fit in a closet. The only trade off is the five to fifteen seconds it takes to change weight between sets.