The matte look is very popular on e.g. social media and on advertising images. The tonal range is shrinked to simulate the look of film. It can be done in LR with the curves tool. You will also need to adjust the colors and contrast to achive a natural look. There are lots of presets that can do this with varying luck, but to do it yourself needs practice and knowledge to get it right. A dedicated tool that can create this effect with a slider would be very helpful and save a lot of time for those who want this look in their pictures.
Have you tried creating or downloading some presets that produce the effect you want, then fine-tune the preset using the 'Amount' slider? I've attached a screenshot showing the location of the Amount slider for fine-tuning preset effects.
Yes, I have downloaded and purchased a lot of presets and profiles. The problem is that they always want to change the colors too, in all sorts of ways. I just want the clean and pure matte effect, without any color tweaks. Then I can possibly make my own changes afterwards. Even though I've spent hundreds of dollars on such profiles, I often prefer one I've made myself, based on the Adobe Color profile.