What Sheets genuinely solves
Two people can work at once, the file is not on a machine that can be stolen, and there is version history if somebody overwrites a formula. Those are real improvements and they are why a lot of shops moved from Excel to Sheets rather than to software. For a small operation keeping a simple list, that may be enough and we would not argue with it.
What it does not solve
A spreadsheet still cannot hold a unit and a conversion against an item, so buying in tons and selling in kilos is a formula somebody wrote and somebody else will break. It cannot enforce an unbroken invoice series or require an HSN code, so both drift. And the ledger is still a second sheet updated by hand, which means it stops agreeing with the billing sheet the first busy week.
Stock is where it fails fastest
A stock column in a spreadsheet only changes when a person changes it, and in a shop that person is always busy. Within a month the figure is decorative. In MaterialBill stock moves because you billed and because you purchased, in the item's own unit, which is the only arrangement under which a shop with hundreds of items has a number worth trusting.
Use both, for different jobs
Nobody should stop using spreadsheets. A one-off comparison, a rate analysis, a list your accountant wants — a sheet beats software every time. Everything here exports to Excel on every plan including the free one, so that work stays a two-minute job. What changes is that the sheet stops being the record and becomes a tool you point at the record.