Then what's the point?

Making it sluggish and bringing it to the PREVIOUS STATE is pointless. But defragging the RAM will give positive effects. It's not like we gain performance by defragging the hard disk. RAM is always allocated contiguously and if the operating system can't find a free block to allocate RAM, then it can't do it. Say you need to allocate 1MB RAM for a new program. Even if you have hundreds of 1023KiB chunks left (that's about 499MiB), you still can't load that program. However, this is one reason to have a pagefile. Then the OS can swap in and out pages and it can make large enough contiguous spaces for new programs. But if your PC isn't a server, it is better to restart the system rather than use these 3rd party softwares, because you don't want your system to crash because of a bug in that program.
