Journals are excellent sources for up to date research but on a practical level they are usually highly specialised, with a natural focus on research rather than teaching and are written with academics rather than students in mind. The language is usually highly formal, with academic vocabulary which students often find disconcerting, sometimes unintelligible. This means that they are not always the best place to go for undergraduates.
Please remember that just because something is difficult doesn’t mean it isn’t good! Just as physical exercise requires effort but is good for us so intellectual effort is required to train the brain.