"Would you like to drink some coffee or tea?"
First let me correct your question. It should be "爲什麽不用~." The subject "we" or "people" referring to an unspecified group of people is redundant in Chinese and we often omit it. The answer to your question is, yes, you can use 想, like "你想要喝" or "你想喝." When meaning "want," 想要 and 想 are completely interchangeable.