Selling and/or leasing of current buildings after the centralisation can lead to:

• long-term financial benefits;
• staff reductions (through natural attrition and less staff being required); and
• efficiency and/or productivity improvements.

I have been been a part of and witnessed the benefits of centralisation in a large Federal government agency.

Council could continue to provide services to areas through eg their numerous libraries and also online.

It is noted that not all functions are being centralised, only a few.

There are numerous benefits, see (for example):

• https://bizfluent.com/info-8065381-benefits-centralization.html
• 
  http://www.strategicsource.com/realize-economies-scale-growth-centralize-purchasing-function/
  https://www.ableandhow.com/should-we-centralise-centralize-our-business-corporate-internal-functions/
• 
  https://www.virtualkollage.com/2016/12/the-merits-of-centralization-system-of-government.html