This is one of the areas in which the Amiga really shines because of directory utilities (like Dopus 4.xx, Ordering, DiskMaster, etc) and the ram disk.
In Dopus, for example, you can assign one of its buttons (or menus) to be "UnLHA". You would then only have to figure out the required command line arguments (in LHA's docs) once when configuring the button. There after, all files compressed with LHA would require a click to select the file and another click on the new button. All of the directory utilities listed above have more capacity to be customized than I can ever need.
Amiga has the best implimented ram disk of ANY OS I have ever used. If you have enough ram, any program, utility, etc can be un-archived to the ram disk and then executed directly from there. You can test the new program, see if it meets your expectations. If you like it, you can find a permanent home for it on your floppy or HD. If not, merely delete it from the ram disk, and nothing in your OS setup has been altered or disturbed. (Try that with any OS that relies upon a registry-like file.)
If this seems like a lot to take on, a number of Dopus users have uploaded their configuration files to Aminet as examples of clever use of the program.