The idea here is that the colour of ribbon chosen for the particular Mass being celebrated can be aligned to match the liturgical colour of the particular Mass. This makes manifest sense when you stop to think about it. If the vestments are of a particular colour, the antependium, the tabernacle veil, as well as other textiles associated to the liturgy, why not even small details such as these?
No one would go so far as to say this is "essential" of course, but for the liturgically attuned mind it shows the level of thought that has gone into even the smallest details that surround the sacred liturgy. It must be said that while is sometimes popular in our time to conclude that any such attention to detail is somehow misplaced or misguided, even an unhealthy fixation, there is no such necessity; it really just reflects the importance assigned to the particular symbolism of the liturgical colours in just the same way that the various signs and symbols of the requiem Mass have a certain internal consistency.
My advice then, be it to priests, Masters of Ceremonies, or altar servers -- whomever has the responsibility for 'setting up' the missal for the particular Mass of the day is this: avail yourselves of these little details, not as unhealthy fixations of course, but simply as a means of showing our care and attention to even the smallest of details of the 'source and summit' that is the sacred liturgy.
