Yeah as stated just a guideline is all. It isn’t going to outright tell you what the odds of a player doing well but it gives you a rough idea of how well they might do. Often the best players are .800 or better.
This also means in some ways that the higher the number the odds of the hitter getting on base often but also getting on base with xbh too. That lets you know it isn’t just gonna be lots of singles and walks but also some doubles triples and maybe even homer’s.
So it boils down a high OPS often means a player can get on base often, and usually do it with XBH as well.