I think the crux is here (from their explanation post):
> extract the most valuable 10 hours/week ...
> ... don’t pay payroll taxes, don’t pay bonuses, and don’t need to offer benefits
How they define a "fractional" is almost 1:1 the definition of false self-employment, which is illegal in many parts of Europe, as it fulfils all criteria of normal employment without any of the security for the employee and circumvention of paying for social safety.
> extract the most valuable 10 hours/week ...
> ... don’t pay payroll taxes, don’t pay bonuses, and don’t need to offer benefits
How they define a "fractional" is almost 1:1 the definition of false self-employment, which is illegal in many parts of Europe, as it fulfils all criteria of normal employment without any of the security for the employee and circumvention of paying for social safety.