If you have large volumes of data I would suggest you take a look at OptimizeRasters. This is a set of tools specifically designed to enable such conversion at scale. This provides a GPTool that runs in Pro , but can also be scripted in the command line. The tool has been used for the conversion of many PetaBytes of data. One of the reasons to convert to MRF is typically to make use of the optimization available in using Raster Proxies that improve access performance by caching previously accessed tiles locally. The documentation provided explained how this can be set up.