This Kathina ceremony is, as far as I can see, recommended by the Lord Buddha mainly for the welfare of the Sangha (the Community of monks). The Lord Buddha did take into consideration how the Order He founded could survive. After the Mahaparinibbana (the Great Passing Away) of the Buddha Himself, the whole responsibility of both perpetuation and propagation of His Teachings would certainly fall on the Sangha. Therefore, the continuity of the Sangha means the continuity of the Dhamma itself. Moreover, after His Mahaparinibbana, we could see the Buddha Himself only once we see, understand and realise the Dhamma. This was the case even when the Buddha was still alive for He declared that one really sees Him only once one sees the Dhamma. Now we can see the logic behind the recommendation of this Kathina ceremony -- how it is important for the cause of Buddhism itself.