Especially combined with the dynamic array formulas that have recently been added (LET, LAMBDA etc). You can have much more going on within each cell now. Think whole temporary data structures. The "evaluate formula" dialog doesn't quite cut it anymore for debugging.

from my experience in the corporate world, i'd trust an excel generated / checked by an LLM more than i would one that has been organically grown over years in a big corporation where nobody ever checks or even can check anything because its one big growing pile of technical debt people just accept as working

If it has a concept of data sources and can digest them, sure. Anecdotally, most issues with Excel at my job are caused by data sources being renamed, moved or reformatted, by broken logins, or by insufficient access rights.

100%