Very few modern African stamps have become rarities, but this set from Burundi is an exception. Increasingly, the stamps of post-independence Africa have become more and more popular, and there are many reasons for this.
First, the stamps are intrinsically rare. As of now, there are only a few thousand serious collectors of modern African stamps. As short as a decade ago, the economic prognosis for Africa was bleak. Increasingly, though, African countries have seen foreign factories open up and mining and resource extraction increase, and so economic growth for the continent over the last ten years has been among the worlds highest. Foreign investments mean expatriates living in Africa, and expats often collect stamps, especially the stamps of countries that they lived in when they get back to their home country. This means that there should be increasing worldwide demand for modern African stamps. Further, much of the foreign investment in Africa is from China, and Chinese living abroad are among the most avid philatelists in the world.
But perhaps the greatest reason for the increase in popularity of modern African stamps is the realization that many African countries use the proceeds from philatelic sales to help further conservation efforts. Collectors of African stamps can enjoy their hobby and feel that a portion of what they are spending for their stamps have found their way into conservation and animal protection measures.