This could be an interesting gift idea. Definitely shows someone that you were actively thinking about them for extended lengths of time while they were away.

It’s also sort of founding example for the idea of social annotation given that most prior annotation was for personal use. (Though Owen Gingerich has shown that early annotations were copied from book to book and early scribes added annotations to texts for readers as well.)
It also demonstrates the idea of proof of work (in this case love “work”), which is part of the reason that social annotation in an educational setting using tools like Hypothes.is is worthwhile. Students are indicating (via social signaling) to a teacher that they’ve read and actively engaged with the course material.
Of course, unlike the example, they’re not necessarily showing “true love” of the material!