This is probably a really niche problem but I sometimes need an amp meter with an illuminated display when I need to characterize some LEDs from eBay that come without a datasheet, for example. In order to see when a LED starts to light up I need to turn down my lights which also prevents me from being able to read the analog amp meter seen in the project image. I could use my DMM, which has a display backlight, but using the 'built in' amp meter of this power supply is just more convenient.
From converting my broken desk lamp to LEDs I had some leftover pieces of LED strips that just seemed perfect for this purpose so I did a quick test and soldered up this prototype:
For the next links there's probably going to be some overlap with references from the above projects but I'd like to mention them nonetheless.
If you have googled the topic you might have come across Phil's video about the topic. There's also some more information in the video description. While on the topic of videos, this one makes a good point why a conversion might not be the best idea.
Now for some detailed tutorials over on intructables:
For my first PSU build I used one of these cheap LED voltmeters that you can get from eBay for less than 2€. The ones I got have a measuring range of approx. 3-30V. The lower boundary is due to the fact that these meters measure their own supply voltage.