There are more reasons for TEXMFLOCAL and TEXMFHOME. Let us first consider TEXMFLOCAL:
- Fonts, style files, etc that are local to the department, company, etc, that cannot be uploaded or used outside the company/school/whatever, but should be available for everyone within the company.
In the same way you can consider TEXMFHOME
- Personal material, privately purchased items etc: I have purchased several font sets, that I am allowed to use, but of course not share, not even to other users of the same computer system. So I put them into TEXMFHOME, where only I have access to.
So it is about proper separation to where the material comes from and for whom it is intended.