A picture book is usually a child's first introduction to art. We can't afford to make that introduction with mediocre or poorly conceived books. Make your choices carefully. Subject is not enough.
Picture books can and should be brought into every curriculum area. You could look through your plan book for the next week and find a picture book to introduce or strengthen every single concept and subject on it.
Any book is fragile. You can kill it or the enjoyment of it by reducing it to a ditto page or book report, forcing your interpretations down anybody's throat, or overusing it. Keep the touch a light one and you'll open doors as well as books