I have detected an anti-textbook feeling from some language teachers and I understand where it stems from. Books are not always good, some teachers use them too slavishly and with poor methodology, some have been poorly selected for a department. They seem expensive. It is also true that in some schools teachers cannot trust pupils to take them home or look after them properly.
On one occasion an HMI told me he was pleased to see my department using textbooks when many schools were not. This is why I think he was right:
A textbook is a collection of resources, part of a package of language learning materials which include a teacher's book, repromasters, recorded language and frequently online exercises. It has, in the best examples, been painstakingly pieced together, often refined over many years, to be a coherent, carefully graded, methodologically tried and tested learning resource. It is a reference book for pupils, a comfort blanket, a resource for overworked teachers to fall back on. It's a place where wheels need no reinventing. A fellow skilled professional has been paid to produce something of quality for you to use.
A good course book need not lead you into poor pedagogy and should be a launch pad for effective listening, oral practice, grammar and vocabulary building. It will be a good source of "comprehensible input", contain authentic sources and provide the teacher with creative ideas for lessons. It will come with a ready-made scheme of work.
On the other hand, course books and their peripherals are expensive, but when you begin to calculate the ongoing cost of duplicating worksheets and buying IT packages, and when you bear in mind a course book should last at least five years, they make good financial sense.
So, provided the course is well chosen and not used exclusively, no department should feel any shame in using a good textbook.