gmmichaeljiang :
Is it better for workstation or gaming or both?
Better than what? For workstation, the AMD chips are the go-to products, as they are significantly faster in each price tier. For gaming, Intel chips are better,but 9th gen brings nothing new in this regard except for better cooling and slightly higher stock frequencies. Performance is in the same ballpark as the 8th gen.
What are your needs? Do you need to upgrade? Do you care about getting the absolute edge at a specific workload? That's all relative because as general-use processors, the value for money isn't there with these chips, and in the higher end they are power hungry. If getting a few extra frames or the tiniest bit of extra single threaded performance out of the box is worth it to you and value is less important, then they are worth it though.
Are they revolutionary? Well, they no longer use toothpaste as a coolant!
That's really the biggest difference imho. Now you can use a 9600k in a tiny itx case and even overclock it a bit using smaller air coolers, like you could with Ryzens, and have a faster ITX gaming rig.