LibreOffice Gives the user many ways to quickly apply direct formatting on characters (like bold, underline, italic). However, the use of character styles to give effects to particular areas of text is useful for when you require to modify the style of certain text (e.g. turn all bold text to italic).
The use of character styles is not very intuitive, though: it requires using the Styles and Formatting window, and trying to find the style you wish to apply from an unorganized list, in which the order of the styles can change (often when I use the strong emphasis style, it moves higher up the list and I have to find it again).
A good solution to this, I think, would be to implement keyboard shortcuts to apply character styles, just like you can use keyboard shortcuts to apply heading styles (Ctrl+1 for heading 1, Ctrl+2 for heading 2 and so one). Alternatively, AutoCorrect could be configured to apply the styles, just like it applies the bold style when you put text between to asterisks like so.
I use this feature a lot, and I believe that implementing it a bit more intuitively could contribute to everyone’s use of LibreOffice. I do not know exactly whether my suggestions are feasible with the current structure of the program, but that’s just how I envisioned it.