(a) The providing of all of the relocation assistances and payments described in this chapter and, in connection with the acquisition of real property for public works projects or programs, the establishing of all of the policies and practices described in this chapter, and the paying or reimbursing of all of the expenses described in this chapter are declared to be necessary and shall and do constitute governmental functions undertaken for public purposes. Therefore, public funds may be expended by said public entities in furtherance of such functions, and those public entities that possess the power of taxation in relation to the public works projects and programs referred to in this subsection may exercise such power in furtherance thereof.

(b) Nothing contained in this Code section should be construed as a grant of a power of taxation to any of the several public entities which do not possess, independently of this chapter, any powers of taxation. Rather, this Code section shall constitute a grant of the power of taxation in relation to the public purposes enumerated in subsection (a) of this Code section to such of the several public entities as possess, independently of this chapter, powers of taxation in relation to the particular public works project or program which is undertaken or sponsored by such public entity and which displaces a person, thereby giving rise to the necessity of relocation assistance and payments, or which requires the acquisition of real property, thereby necessitating the real property acquisition policies, practices, payments, and reimbursements described in this chapter.