When PS3 appeared, its hardware was significantly better than its contemporary PCs. It was definitely worth to get a console to run games that time. PS3 made many PCs obsolete then. But this time the hardware of PS4 is weaker than mid to high end gaming PCs'. Unlike PS3 era, if you would like to play games at higher resolutions or at better quality, it is worthwhile to go with PCs this time around. However if you run games on PCs with low to mid-range cards, you are probably able to play games better with PS4 than your current PC setups. In short PS4 won't make all the current PCs obsolete but you need good PC setups to beat PS4 in gaming performance.
Unlike PS4, PCs can do many things. PCs can play a vast amount of older games in the past 25 years as well. There are many new Indy game titles only for PCs too. Then if you already have a PC with mid to high end gpus, I really don't see a benefit of getting PS4 unless there are PS4-specific game titles that you really want to play. On the other hand if you currently only have a laptop computer for general usage but want to play games casually at an adequate resolution, PS4 is a good way to go. Consoles are significantly cheaper than building a PC with mid to high end gpus. IMHO whether PCs or PS4 is better actually depends on each person's situations.