Weight training exercises, barbell curls pointless for a trackie?

I wish this was true...

You will not get good core strength from cycling alone. I learned this the hard way...

Cycling can and will overdevelop certain muscle groups to the detriment of others and can throw your body out of balance if your core is not strong and stable.

Yes. This is exactly how I damaged my back. The physio took one look at me and said it was so obvious I was a cyclist. As she put it "My core strength is a joke" and I have very overdeveloped quads compared to pretty much everything else