You are saying it is for travelling, but i'm huge fan of everything that can save space in any day-to-day situation. And if it is really like 3 bottles of shampoos than it worth it ! Less plastic, less trash, less time to the convenience store. :)
I Love to use the solid shampoo because the ingredients in it,like karite butter,mango butTer ,coccoa butter,olive oil etc are soft to the sculp and helps to keep the capillary hydration.