Photos to Slides is quick and easy to use but there are a couple of things that you should note before you try it. First, you need to make albums in Google Photos before you use the add-on. Second, the free version of add-on limits you to 50 images imported at a time. Third, the reviews of the add-on are mixed, but I haven't had problem using it.
Applications for Education
The person who asked me about this add-on was making an end-of-year slideshow for his school. That's a common use for Photos to Slides at this time of year as it could be a big time-saver for anyone charged with making end-of-year slideshows.