Phil Seamark provides some advice:
Column splitting is an idea worth testing when you are looking to reduce the size of a large semantic model to potentially reduce the SKU required to host the model. The good news is, the technique can also benefit the time to load data into a model and speed up your DAX queries.
Instead of storing each complete value in one column, split the column vertically and store it in smaller pieces. Then use a DAX measure to combine the pieces back together. Those pieces often repeat more frequently, which can help Power BI compress them.
What’s interesting is how similar this approach is to financial systems from back in the day, where all money was stored as two separate integers. In that case, it was for the sake of precision and correctness rather than performance, but it’s nice to see these techniques still kicking.