Absolutely. And the data and code being stored all in one file makes it exceptionally nimble for the planning phase. You can generally count on any stakeholder in your org being able to handle it.
Budget planning, presumably. How much you are going to spend and on what, and what you need to charge for your products to break even or meet a profit goal.
I don't know how true it is today, but many a rollercoaster has been designed/planned in a spreadsheet. g-force and speed analysis, making sure there aren't any "blackout" points, etc. It allows you to iterate quickly and automatically appreciate the ramification of design decisions.
Pivot Tables was the last big feature completely missing, which is now available. Numbers might meet most of the spreadsheet requirements, except some scripting requirements. There is Applescript for those who are inclined that way. For my own use cases, I use LibreOffice Calc, even on macos. I started using it an year ago, just to see if it can work at all. So far, I haven't had any blockers, but my usage is probably not so complex.
There is no other planning tool in the software industry that can answer “what if I changed that” as seamlessly as excel.
Planning is not about its absolute numbers but about its sensitivity to inputs and assumptions.