In no particular order:
- little danger of enforced obsolescence of file formats
- no risk of data being infected with third party copyright
- high security from malware
- availability to export/save as pdf from any program
- no need to trace licences and observe arcane licencing requirements
- no problem with duplicating of machines - no need to wait for additional licences
- little risk of unauthorised copies of SW run by employees at work
- ability of employees to run identical software at home for evaluation / training purposes