I disagree.
Let me give you an example. Some years ago,the irish police had a grievance, they were paid less pay for holidays than normal working days. This was because when on holiday they were just receiving their normal salary and weren't getting certain other expenses.
In other words, these expenses weren't real expenses but a form of tax-free pay.
They had been introduced as an under the table pay increase during some negotiation or other, probably as a way of hoodwinking the taxpayer/other workers or circumventing some pay-cap or other. As I understand it this type of thing is/was common in the public service.
There have been moves towards openness.
Already lists of government payments to private contracters are published in Irish newspapers.
Also lists of tax defaulters and details of their settlements are published regularly.
Public servants having their salaries and expenses published is just another step further down this road.
The same should apply to welfare recipients.
Being able to see who spent what, where and how is probably the greatest way to ensure tax money isn't wasted.