The "work value" is not called into question by the basic income. It only regulates what belongs to the individual by right, not the duties he has towards society. These remain intact.
Basic income does not prevent anyone from pursuing a gainful activity. The human being is naturally active and creative.
By decoupling work from basic income, the dignity of the worker will be based on a freely chosen activity (paid, voluntary family, citizen or other; full, partial, casual, seasonal, etc.).
If the jobseeker has the means to refuse an offer, then the freedom to contract can really apply to the labor market.
Businesses will also benefit from the system. They will no longer have the role of financing the survival of their employees and their families, but rather of motivating employees to the life and objectives of the company.