These results give rise to several important considerations. Firstly, the results obtained with our method demonstrate that, despite the fact that our model reproduces globally well the explored thermodynamic properties across the different conditions, the performances of OPTI-3T are not distant from those of e.g., OPC3 and TIP3P-FB. This demonstrates that, substantially, there is a limited room for radically improving the performances of three-site rigid water models. All our results suggest that there is an intrinsic limit in the accuracy that is achievable with models where the representation of the water molecule is so simplified. This leads us to fundamental questions. What are the key factors underpinning such limits? Are these imputable, e.g., to limitations in the optimization method itself, or to intrinsic limits of the model? In the next section, we will deeper investigate these questions, obtaining interesting insights.