Insightful fighting is a good option to have
Yes, attacking with advantage, as well as sneak attack, when hidden is great, but there are at least two reasons that Insightful Fighting could sometimes situationally be the better choice for your bonus action.
- Hiding isn't always possible
Just because your Rogue has Cunning Action and can hide as a bonus action doesn't mean that hiding is an always available option. The location of your combat is vital. You're unlikely to have many fights on an endless unbroken plain but that doesn't mean that there's always going to be a good place to hide within 30 feet. Hiding may not always be possible - though it'll be easier if you're a lightfoot halfling so can hide behind other players.
- It lasts for up to a minute
This benefit lasts for 1 minute or until you successfully use this feature against a different target.
If you're using your bonus action to hide you only benefit from it on a single attack. To get the same benefit next turn you'll have you use your bonus action to hide again and so on, for as long as the combat lasts - that rules out any other possible uses you have for your bonus action.
Insightful fighting on the other hand could last for an entire minute. Once you pass the check, and gain the benefits of Insightful Fighting, they're active for up to 10 combat rounds (ending prematurely if the creature dies or you use the feature on a different creature). Not many combats last that long, but against one or two big enemies, as opposed to lots of minions, that's up to nine rounds where you can do something else with your bonus action. Sure you don't have advantage on each attack - but now (among other possibilities) two weapon fighting is an option. If you miss once you get a second chance to hit with your sneak attack (and two chances to crit) - and if you're lucky you could hit twice.
A final reflection:
Insightful Fighting is on the whole going to be more useful for melee rogues, who will find hiding more difficult. To attempt to hide they'd often have to take an attack of opportunity, as they won't be able to use their bonus action to both hide and disengage on the same turn.
Conversely, it's going to be less useful for ranged rogues, who won't benefit from two weapon fighting and won't have any need to disengage - but it can still be a useful choice for either of these players. Both these rolls have a chance to fail, so a ranged rogue might choose to hedge their bets by using Insightful Fighting to guarantee sneak attack for up to ten rounds and then still attempting to hide with their bonus action on subsequent turns to gain advantage as well.