The point of Romanisation is to make it possible to at least mentally turn it into "sounds" for those familiar with Latin alphabets, who (except German speakers

The point of Romanisation is to make it possible to at least mentally turn it into "sounds" for those familiar with Latin alphabets, who (except German speakers) generally expect to see spaces between words too. Japanese writing doesn't use spaces either but all the standard Romaji transliterations do make use of spaces.