Misprint or printing slip?

The collector of Indonesian stamps is regularly confronted with this. In addition to the stamp series that are simply for sale at the counters, non-standard stamps are also offered. These are, of course, not available at the counters! As an example, I have taken a series that was issued in two parts. The series was issued to commemorate five years of the development plan. The first part was issued on August 17, 1969, and comprised stamps in denominations of 7,50, 12, 30, and 40 Rupiah. The second part of the series was issued on September 27, 1969, and had values ​​of 5, 10, 15, 20, 25, and 50 Rupiah. However, deviating stamps also entered the market through various stamp dealers. Such as the 7,50 Rupiah stamp without yellow, the 30 Rupiah without grey and black, and the 40 Rupiah without yellow and orange but with a pink color. Also, the last two stamps are unperforated on the left and right, and the perforation runs vertically through the stamp image. The same type of deviations occurred in the second part of the series. How was it possible that these kinds of deviations could be offered? Some catalogues include deviations, but far from all. Are these stamps collectible? One says: worthless printing rubbish, while another says: I wish I had them! The images on the deviating stamps correspond to those of the original stamps, only the colors are different. But it gets even crazier when stamps appear with a different design. What is going on with those? Are they proofs or something? An example is the 15 Rupiah stamp, where the standard issue shows three bobbins of a loom. But on the other stamps, only one bobbin and in a completely different design. What is your opinion? Collectible or not? Do they belong in the stamp catalogue and stamp album of Indonesia, or in the trash?