I used Excel heavily, with longish macros, do be able to program at all (in Engineering, not IT, not allowed any development tools), and was able to write a lot of what (were not then called) "apps" - specialty programs that did one thing. Custom reports and updates, mostly; A button would refresh a pivot table directly from Oracle database; another would put changes back in to Oracle, after data filtration.
Calc is pretty lame at many things that Excel really had nailed down well, 20 years back. Casually tossing of Macros that do database hits or invert pivot tables is just easier in Excel.
Thing is: IT Dept. HATED ALL THAT.
IT totally hated user programs of any kind, even when they were far more stable and reliable than their solutions. Even small ones that did one thing.
My solutions were always up for being replaced by some more-difficult usage of their Big Solutions, like PeopleSoft or the Formark Document Management system. Only the fact that they were so slow to deliver - by the time they'd started the project in earnest, the business needs would have changed; I'd adapt my Excel macro solution in a few days, and they'd be back to square one on a year-long process - kept my solutions going for years.
So, the bad news is that you won't be able to do some of the cool power-user solutions with Calc that you could with Excel; the good news is that your IT department will be happy about that.