This is sort of a modernized web-based PokerStove. It's useful when you are at the stage where you are deep analyzing past hands or perhaps deciding whether preflop shoves in tournaments were good.
But I think even as someone who has used PokerStove in the past, and has programmed some range evaluators, the UI is pretty intimidating for me.
Equity and range evaluators got a lot less useful because people figured how to make software that solves the full (simplified) game tree. This is a superior approach to anything other than all-in spots (which have game tree of one nodes.)
Most serious players these days primarily use software like pio and monker because the competition has gotten tougher and old equity calculators are like using a graphing calculator vs a
But I think even as someone who has used PokerStove in the past, and has programmed some range evaluators, the UI is pretty intimidating for me.