A normal finance team gets constant one off requests for information. Download something from the ERP, lookup against something else, pivot it by department. Then you get a follow up for the same but with x excluded, but they need it in 10 minutes before a meeting. Excel is great for that.

Then there are the dozens of files behind accounting records. Take a Fixed Asset Register (since it is at the top of the balance sheet), a list of your assets and their depreciation schedule. Maybe your ERP doesn't have one, or your company didn't buy that module, or you have a special class off asset that doesn't fit in it. Maybe they coded it for one country, but in your country the rules are different, so it ends up in Excel.

Then maybe you have a bank account and you have cheques that are posted to your ledger but have not cleared the actual bank yet. Then you have items on your real account that you couldn't post yet, maybe someone paid you with no reference. So you keep a little Excel reconciliation to check.

Then inventory, maybe the ERP didn't split it in the way your consolidation needs it, so you transform the data in Excel and reconcile it back

Then you have all the things that belong in this accounting period but haven't been billed yet, so you have a running list of accruals and when they will reverse. Then you have all the things that are posted in this period but relate to later periods, so you keep a prepayments file. Maybe both of these spit out a journal to upload back to the ERP and reconcile the balance.

Then you get a download of the payroll for the month, but you need to rearrange it into net pay, gross pay, taxes paid by the employee, taxes paid by the employer, pension contributions... then you have to split it by cost centre too. This could be coded, but it is different in every country... and the cost centres keep changing, and the analysis head office wants keeps changing... so it goes in Excel.

Then I want to verify that the system posted the correct absorption to inventory, so I paste in an inventory report and a TB and last month's reconciliation updates.

I can code, but I can't maintain 100 pieces of software that change all the time. I also need all the people in the chain to be able to follow it....

And yes, finance people know how to apply the famous 'checks and balances' to keep out most classes of mistakes....and to detect the same mistakes made by the engineered 'proper software' we have to work with.