No lid leaves some opportunity for contamination. You would be taking a chance using that yeast again. It’s probably fine. A lot of things in home brewing are about mitigating risk. It cannot be eliminated. Each of us have to make up our own minds about how much risk we are willing to take. Those with different tolerances for risk often think poorly about those with a higher or lower tolerance than themselves and speak disparagingly of them. Kind of a metaphor for the world we live in today.