What that does is basically create a new morph that combines all the morphs that were currently applied to your model. While it is a 'single slider' it is not the normal way to make a 'single slider morph'. There are also limitations, and I should know, because I have been doing the single morph and conversions for quite some time.
First, the typical 'single slider' morph is not a morph at all, but rather a control morph. It does not do any morphing on its own but rather allows a single slider control over however many morphs you have used on the model. It still requires that all the morphs be installed on the system you are moving it to. And, it requires that you package the control morph with your character .duf file.
Second, the way ITRoy described how to do it actually came to him, via a third party, from me and what it does is create a new morph by exporting and reimporting an already morphed character. The issue with this approach is that unless you are a DAZ PA, you can only export and import base resolution characters. so not a single HD morph is exported into your model or imported as a morph when you bring it back to DAZ. The other issues deal with ERC freezing, which must be done to help mitigate posing issues. But not every part of the ERC freeze process is beneficial. When you have heavily morphed characters, and are only using the supplied DAZ internal tools, you can end up with a lot of odd results. The the last issues is a pet peeve of mine and sometimes in a rush I am guilty of the same thing. Since most of the time you are taking a complete character and exporting then importing, we forget to remove morphs such as fingernails, navels, nipples. This forces the new person receiving the morphed character to either figure out how to undo those options or be forced to live with them. That is almost as bad as leaving genitalia attached to the figure when you save your morph.
While using this second method would mean that your .duf file will have fewer entries in the modifiers section, that is not the major determining factor in how fast your character loads. DAZ is very bad with memory management and resource allocation. DAZ will load every single morph you have installed in your library for the generation of character you are loading. And, DAZ does not do any instancing of those morphs, so if you load a second character all of it's morphs are loaded based on generation. That means every slider, every icon for that slider, every character slider of that same generation.
The last issue is that someone somewhere in the chain of custody of that character has to have all the morphs required for that character installed. It could be the dev, but usually isn't, it might be the second, third or fourth person using that character .duf. That individual then has to want to go through all the work it takes to make a base resolution morph for that character .duf file and make sure it is included with all their copies of the character moving forward.
So, now we know that you do make your own morphs and I do the same, but do you actually share your versions with the morph you create included? Does it install with DIM or even manually and do you tell people where to install said morph? Since you want to keep you profile secret on this site and I can't see if you actually share your .duf file and the .dsf file you create, I am going to assume that you don't share. So telling others that they should do all the work and save it the way you want it saved seems a bit entitled, doesn't it?