Those who are devotees of other gods and worship them with faith, they also worship Me, O son of Kuntī, though not following the proper procedure.

An inclusive declaration: all worship reaches the Lord, even if indirectly. Anya-devatā-bhaktāḥ — devotees of other demigods — have sincere śraddhā, but limited.

Avidhi-pūrvakam — not according to the proper procedure — indicates they worship Brahman through partial manifestations, not directly. Like watering the leaves instead of the root.

The Lord does not reject this worship, but indicates its subordination. All demigods are His expansions, so worshipping them is worshipping Him indirectly, though less efficiently.