I do find REL/MIN/MAX measurements and temperature much more important than a dedicated LED testing function (I already have dedicated testers, I'm just too lazy to pull it for quick checks while working on a circuit) but YMMV of course.
Personally, I just use a bench power supply and a resistor
The PSU is always there on the shelf, as is a range of chunky resistors and other passives that get used for lots of assorted jobs like this. A dedicated tester would take up space, require battery changes and occasional testing, calibration, etc... Overkill really, especially for such a simple task.
Certainly, I've never attached great importance to a DMM being able to light an LED in diode-test mode, especially as the test current varies so much from meter to meter, and is generally only a couple of milliamps at best. But, some reviewers do, which is why I feel I should mention it in my reviews. But then, I see a lot of folk using DMMs when really they should be using a 'scope - it sometimes feels like we're going back to the old days when many people couldn't afford a 'scope
But the dedicated LED test function on the Fluke 18B+ is interesting to me. But not for the obvious reason, however. Instead, I'm keen to see what safety precautions they've taken - because an LED tester socket on the front of a DMM is arguably no better than the transistor tester on a DT830