Do you not know how to read equipment specifications?
The 2409 does not raise and lower. Does not swivel. Does not rotate to portrait mode. It has lower resolution (1920x1080 vs 1920x1200). Has lower contrast ratio. Only has 2 input types when the 2408 has 8 types. Has lower brightness. Has slightly larger dot pitch. Lower viewing angles. Etc. etc. etc.
Look at the specs yourself... it's not rocket science.