*Erm, well, not really! They just don’t scale especially effectively.
Complex lookups between the sheets of a workbook often devolve into a tangled mess of vlookups, offsets and index matches, which are slow to compute and a nightmare to maintain.
Sharing is all or nothing. Everybody in a team needs full access to a spreadsheet even if only to update a few specific cells. Cross-team collaboration usually breaks down to e-mail chains of spreadsheets, lost revisions and manual copy/paste misery.
We’re working on an alternative: a new do-it-yourself approach to modelling business problems where the same data and calculations can be used by different people for different purposes at the same time. An early version is being used to solve real world problems for businesses today. A public preview will be available in a couple of months.