Work. I count 5 profiles on my current laptop. I like to compartmentalize my work/external projects, so I don't mix things like search histories, multiple Google accounts, etc.

These are the profiles I currently have:

1. Default, personal. My personal Gmail and other sites.

2. Non-profit that I run, signed in to its Gmail and other email account, etc

3. 3 profiles for different volunteer/contract roles, each signed in to their Gmail and other accounts.

One example - my shopping profile runs the extensions Rakuten/Honey to find coupon codes. I don't want those running on every single page I load outside of the shopping intent, so I use a separate profile.

Firefox's containers don't allow for limiting extensions, so you have to use profiles. Chrome only has profiles.

I use it when I need to log into multiple AWS accounts.

I have separate profiles for personal/work.