As a CPA I can attest Excel is really useful for financial data analysis and problem solving. It takes time to learn, and there are limitations to manage, but when you know what you’re doing it really gets out of your way so you can focus your attention on the work product instead of the tool.
On how I got efficient, when I started my career I tried to optimize any task I had to perform repetitively, and after 3 years everything was pretty fast. After that I tried to optimize one process every month, and now I have a pool of ideas to pull from when problem solving.