A rupee saved is a rupee earned, A rupee earned is a rupee invested, A rupee invested is a rupee compounded.
The effect of compounding is real. Our spending decisions today will significantly impact our future financial situation. Saving and investing early on can enable great financial success. When invested well in equity markets like index funds, the absolute money generated through compounding in your later years will go much longer. The returns over the long term will beat inflation.
Accelerates financial independence
Frugality is more immediate in terms of its effectiveness to save more money. Income increase may take time and a lot more effort in terms of upskilling. There are however benefits to Frugality beyond just the money aspect. There are lifestyle benefits that come attached to it. It helps discern what is important and what isn't.
You will have plenty to do
Most likely frugality may mean DIY which would mean doing things on your own. When you are not paying someone to do the job for you like cooking etc. You will pick up a skill along the way and have plenty to do. In the current ongoing COVID pandemic, it this may be better than some who are speculating in the stock market.
Inherently you are letting go of wanting things to be absolutely perfect all the time. When you pay a premium you expect to get the top-notch service. Unknown to us our expectations and desire start increasing. Naval Ravikant has a very interesting take on this. He says "Desire is a contract that we make with ourselves to remain unhappy till we get what we want". Through frugality, you can break the expectations and desires cycle indirectly by choosing the option that does the job but may not be luxurious or the most convenient.
When used correctly, frugality would help you focus on life's simple pleasures. More often than not this may mean doing things together with your spouse/family. Contrasting a home-cooked dinner vs a restaurant dinner. Both have a time and place for that. However, when the family gets involved in the home-cooked dinner, it becomes an activity that brings the family closer. The kids may do it grudgingly, but don't worry. Science has shown that kids who do chores are more successful.