Thanks for the question! Here is where the terms "paradigm" and "paradigmatic" may be more useful than canonical, at least initially. One strength, perhaps the strength, of Canon 603 is its ability to provide a paradigm of what it means to be a hermit in the Roman Catholic Church. In other words, it provides a model of what the church considers to be paradigmatic of such a vocation (that is, essential, characteristic, typical, worthy of following or modeling oneself after, etc). All other hermits in the church, whether canonical or non-canonical can be deemed authentic or inauthentic based on how well they live or embody the defining elements of this paradigm --- just as is true for solitary hermits bound legally by the canon. If someone wants to try to live as a hermit and wonders what is involved, c 603 will let them know that --- at least in outline form.
However, canon 603 is normative in a second sense as well; namely, it provides a way for hermits to make public commitments to the life which bind the hermit in law. It provides not just disparate elements found in every authentic eremitical life according to the church, but an ecclesial framework through which one may make a public, legally binding commitment intrinsic to and commensurate with the seriousness of the vocation defined therein. It implicates the entire church in such vocations and establishes legal and moral relationships between the hermit and her bishop and delegates, as well as more casual relationships between the hermit and the rest of the faithful in both the local and universal church. Here is where the importance of a public commitment comes to the fore.
Because the canonical commitment is public and not a private one, it can be and is binding in a way that affects (and makes the hermit deliberately and legally responsible for) the upbuilding of the church as a whole via this vocation. It allows others to have expectations of this hermit and the vocation as a whole, especially that eremitical life generally is not a means to a selfish and defensive cocooning, an expression of misdirected individualism, or the work of something other than the Holy Spirit in the Church's midst, but is healthy, life-giving, and part of the holiness of the church herself, and also that this person in this place and time has been truly called to proclaim the Gospel with her life in this unique and rare way. These characteristics are also linked to the affirmation that c 603 vocations are ecclesial vocations, belonging first to the church and only thereafter to the hermit called in this way.
Though everyone is called to live their vocations with integrity in a way that edifies, not everyone is called to take on the same public responsibilities and rights, however. Not everyone should attempt to do so. There are several paths in the church to eremitical life and many more outside the church. Only two of these are considered canonical and are seen to be both paradigmatic and legally binding on those whom God has consecrated accordingly. This "standing in law" that comes with profession helps the one called in this way to truly live the vocation in an exemplary way. It provides a specifically ecclesial context where the person can explore the depth and breadth of such a vocation and it ensures the person's commitment to doing so is carefully, consciously, and seriously made with God at the center and the wellbeing of the entire People of God in mind!