I have 2 single-stage presses, and a 5-station Hornady progressive. One single-stage is in the garage... that's where I do all my rifle resizing, it's a bigger (Rock Chucker) press for sizing the larger brass I have. The smaller single-stage (an RCBS RS3) is upstairs next to the Hornady. I use it to process my rifle brass other than sizing... flare necks, swage primer pockets, etc, and to assemble most of my rifle cartridges. I use the progressive for all of my handgun loading, and I've been known to assemble some rifle cartridges on it, too... like 5.56mm, 7.62mm, and even .30-06 (for the Garand.) It saves time otherwise.
I would not want to be locked into using a progressive for everything... that's just me, nor would I want to use only a single-stage press for everything, particularly large volumes of handgun ammos like .41 and .45ACP... although I've done it. Golden Rule: Use the Right Tool for the job...