It is profitable to work under employment contract!
From moment of concluding employment contract, you are employee who has labor rights and social guarantees.
In case of illness, you still get paid.
Employer pays single social contribution for each declared employee. This is your cover in case of illness, work-related accident or occupational disease.
In case of incapacity for work, you will receive cash payments that compensate you for the loss of earnings due to illness.
Payment of single social contribution from only part of salary significantly reduces amount of benefit. If you are undeclared, you cannot count on help. Unless the employer will pay it of own free will.