Hi Terocas, my first impression is that the tickets are good value, and that it will be up to you as to (a) can you afford it, (b) can you fly that far in economy (c) do you need to be spoilt in Business.
I flew economy for too many years in the old days, and now I need to arrive refreshed after being looked after. Is it worth it? You bet it is!!!!!. I do the CDG flight once a year, it leaves at 1.30pm out of Paris, so they will come for you in the business class lounge and escort you to your seat. With a glass of champagne in your hand you can play with the seating and watch the passengers board. You have a lunch setting, relax and watch a movie before dinner, a liquer and coffee after then press the buttons to lay down and they wake you 1 hour out of Bangkok for breakfast. You will be escorted to the TG lounge for a shower, maybe a walk around the terminal to get the circulation going then onwards to exotic and charming Hanoi. Once again would you rather have that or cramped into cattle class down the back. I am very happy to pay the extra, enjoy whatever you decide, regards bkkrop