I think it is a good idea to sometimes put babies down drowsy but awake so they can have the opportunity to learn self-soothing to sleep. If your baby cries hard, immediately pick the baby up. If your baby makes sounds that are not hard crying, wait and watch. Success is more likely if you start this practice sooner rather than later. Success is more likely to occur in the mornings when your baby is best rested from night sleep and for some babies it makes no sense to do this in the evenings around 6 weeks of age during peak fussiness. Also, if it never works, for example with colicky babies, forget about trying it until the baby is older. Success might be more likely if father (or anyone else besides mother) puts baby down after soothing and mom is out of the house. Success is also more likely if the intervals of wakefulness are short (30-90 minutes) so they do not develop a second wind.
I am interested in your own observations and experiences whether successful or not in making these attempts.