Hmmm, not engineered properly would be up to the designer.
Its a good point though.
Failure will always have started at a stress raiser and the stress raisers that the square cut holes/tabs produce could be an issue if you are marginal on your FOS.
Still it could save you *hours* and while I don't guess it's cheap could actually save you a substantial amount. If nothing else in not wasting material, not using cutting disks, electricity, not having to buy bandsaws, holesaws, cut-off saws etc.