I've been looking for something exactly like this, actually! I'm making a hardware device that is a habit tracker, and the screen will be a few 7 segment displays. Being able to simulate the displays like this is very nice. Also very cool that it displays whatever you type in!

Yeah, and you can even customize whatever segments the display is showing, even if they're not Basic Latin alphabet or numerals. It's not my website, I posted it to HN because it's something of interest to technology.