The simple answer is, reversible convertible designs help you save time, money, space and energy. And they are also great for the environment.
Save time - you have more looks in 1 design, it reduces the needs and time spent on buying more clothing to look great without repeating the outfits. It also saves the time spent every morning think about what to wear.
Save money - you buy less and better now, so you save money.
Save space - your closet and luggage will thank you. They won't be so packed and crowded anymore. As now you have quite a few Swiss army knife like designs to wear and do the job!
Save energy - energy is saved on maintaining, carrying, storing and disposing garments as now you have much less. Mental energy is also saved to think about what to wear for different occasions.
We have a very detailed guide on the 10 benefits of reversible/convertible designs, read if you have time.
Last but not the least, since you consume a lot less clothing now, you are also helping to save the environment. Less clothing is needed to be produced; energy and resource is saved for where it is needed more than producing clothes.