MarkXu,
It might be helpful to consider your use case for these machines. I am a professional tradesperson, so my considerations may be different than that of a consumer.
To my way of thinking, "daily driver" tools or tools that go up a ladder benefit from cordless technology.
On the other hand, good quality, professional tools tend to last a really long time. I spent much of my career performing on-site, residential remodeling work (slowly transitioning the business towards Shop-based production of windows and doors). With the remodeling work, I often performed every stage of the project, from form work to finish carpentry and touch-ups. I bought into the HILTI 18V (which morphed into 22V) cordless system. The tools are top-notch, but what I've found is that now HILTI has migrated to a new battery platform (NURON).
So, now I have a pile of tools (various drills, impact drivers, recip saw, impact wrench, rotary hammer, chargers, radio, collated drywall screwdriver, drywall cutout tool, angle grinder, etc....) that each likely have 10+ years of life in them, but the batteries are now discontinued, and I'm faced with the option of buying up extra (unneeded) batteries now, or if I just continue to use the tools as I have been, and roll the dice that I'll still be able to get "A-22" batteries in 10-15 years.
Festool has a track record (just like all of the other manufacturers) of changing battery form factors over time, so in my mind any cordless tool should be considered "disposable", or be ok with the tool being unusable if/when access to batteries dries up.
Going forward, I'll probably go back to buying mostly corded tools (with the exception of a core set of drills/impact drivers), since I can count on one hand the number of tools I've actually worn out.
So, circling back to your question about the KS(C)-60, I'd suggest asking the question: "Will I get the full value out of the KSC-60 in the next ten years, that I'd be fine tossing it?" If the answer is "Yes" then go for it. Otherwise, if this is intended to be a low-use or "lifetime" tool, then there's a certain stability in buying a corded tool.....