I hate converting spreadsheet apps into a real system because users get so used to ad-hoc fudges and additions they can't handle the rigidity of a real system.
You don't realise it, but you just described why people use Excel and why it's a VERY GOOD tool for what it does.
Most of such rigidity is necessary for chain of custody tracking etc., but they just can't resist the "fudgit urge" for quick fixes. Eventually they get used to it and even appreciate how it keeps things in the right lane, but they are grumpy during the learning curve.
That rigidity is needed from a corporate POV, but it hinders the actual work of good managers that use that flexibility to, well, manage their department: adapting to changing conditions and requirements by creating new models and workflows, without the need to build a full software toolchain.
These people complain because you're taking away useful and powerful tools that they rely upon for their job.
Developers usually don't understand the compromises that users face when you take away the flexibility of everyday human-managed tools and replace them with rigid "well-engineered" software, that crystallizes today's workflow and reduces the possibility to create new ones.
I wonder why there's no more people building Excel replacements that would help with that"robustness and company accountability thing"; I'm sure there's a real market niche there.