Your computer’s RAM is still faster than even modern solid-state drives. RAM disks take advantage of this, using your computer’s RAM as a lightning-fast virtual drive. But you probably don’t want to use a RAM disk, anyway.
RAM disks are easy to sell — all you have to do is hold up performance benchmarks showing how much faster it is to read data from RAM than it is from even a fast SSD. But this isn’t the full picture.