What's your view on sketchbooks in elementary school?

Now that art class counts towards report card grades, I feel like I can hopefully start sending home some "homework" assignments with students and give them the opportunity to have their own sketchbook, something I know a lot of the students in my district wouldn't get at home because of their parent's income.  I don't, however, want to bog the students down with MORE homework on top of what they already do, so this is what I think I want to do.

I want to give weekly sketchbook assignments as a way to enhance a grade, not take away from it.  My thought is that they will be purely optional and those who do them will get a boost to their grade but it won't harm those who don't want to do them.  I know what you're thinking...if they have a sketchbook with optional assignments, they're not going to do them.  I found these book binding kits on-line and ordered a kit to do with my extended day kids.  Yesterday I had my art club kids make a book for themselves so I could give them a sketch assignment to work on while we finish up the mural.  I'm hoping that if the kids actually make their own sketchbook and design the front cover, they'll actually want to keep up with it more.

Eventually, we will do a mixed media collage to design the front of our sketchbook covers...and that's what I would plan to do for their first project next year...design a cover that represents themselves.

I also want to treat the sketchbook more like a sketch journal.  It could be a place for students to write poetry or short stories and illustrate their words if they want to.  I plan on giving sketch assignments that will somehow incorporate words, like a regular journal, and a sketch of some sort.  If they don't do it, they won't lose points, but if they do the assignment, they can earn extra credit points on assignments.  Some assignments may link with things we do in class, some may not.  I'm thinking of doing this for 5th and 6th grade next year to see how it goes...