In the city and around town, the two cars will feel very similar is many situations. Even if you take it on the hwy, yes, one can question is it worth the extra $$$. Compare Civic LX to Accord LX.
Now, try be on the road for 15 hrs. That's where the difference becomes night and day, especially if the Accord is a V6 EX-L (Touring). The better insolation, better seats, stiffer platform, larger size, bigger tires, smoother engine, better stereo, etc.
I've I driven a Civic for 15 hrs? Yes, it's not bad at all. So am I contracting myself? No.
The best way to say it is, once you own an Accord (V6 EXL), it's hard to go back to something like a Civic LX. You can then better feel, hear, and experience the difference.
Note. Experts have said the Accord is noisy and not that well insolated. I never own a Lexus. So to me, the Accord is > the Civic. Therefore, worth the $$$$ regardless of size.