Bike box or bag?

Admittedly if I was travelling as often as you I would invest in a dedicated bag but if I was travelling just once or even twice this year I honestly would just get a box(the one I spent a few minutes rigging up could easily have been chucked in the shed and used again, which, if I was going abroad again soon after said trip I probably would have done). I just feel for people travelling once or twice with no planned trips for the foreseeable future, getting a bike box is a good way of cutting the costs associated with flying or going abroad with a bike. Perhaps I should have been clearer, I think buying a bike bag for a one off trip is ridiculous and unnecessary. Obviously everyone would rather "put it in a bike bag, all pipe cladded and cable tied up, few tools in the nicely designed pockets(nicely designed pocket?!)" but the reality is for someone less well endowed financially than yourself perhaps, an unemployed student for example, this could be a much more viable alternative. You could easily spend a few hundred quid on a bag, money that you'll most likely never recoup.