The downvote is probably because the comment implied that the issue is that the image processing is done in "unsafe" C++ and that another language should have been used.

However, there isn't much choice. Performance is very important in image processing, so much that many libraries contain hand-written assembly. In the article, it says that 90% of processing power is dedicated to it. Using a safer language in a safe way could completely kill performance and significantly increase the costs.