Yes, indeed. If you leave out spaces, you have to have a unique way to mark the beginning of each word (tp speech streams are not generally uniquely analyzable). The shift to hiragana will not do it, since it might be a proper adjective -- and it might not be even if the next character is also hiragana. Having tried to read ancient texts, where spaces were not used, I can assure you that it is not easy to do. As always, of course, I say what is wrong with the Latin alphabet? On the other hand, if what you want is decoration, where the actual content of the sentences is not important or is well known, then, of course, anything goes.