My Take
Haiku Deck has a very simple interface so it's easy for students to use, even at a young age. Students select a theme (basically a format for how/where text will appear), they choose an image, and they type and format text. There are not a lot of customization options compared to PowerPoint and Keynote, but I find that to be the benefit of using Haiku Deck--it's easy to be successful without being overwhelmed. I hope they don't continue to add lots of additional features, I like the quick and simple workflow. The app is rated for 12+. Given the topics that my students are searching we haven't found any images that are inappropriate. We do brainstorm words to use in the search bar and if students want to search something that isn't on the list they need to ask me.
How I Use It
I use Haiku Deck to create quick presentations to use as hooks when introducing a new topic. In addition, students use Haiku Deck to create presentations to demonstrate their learning. They often create a presentation at the end of each unit. Students can create a 5 slide presentation in 15 minutes so they can quickly show me if they understand the main concepts and some key details of our topic.