However focused offsite to solve a specific business issue can be very useful. They might be managers only or everyone depending on the need.
It's easy to say that strategic thinking and planning should be continuous, but in reality there's always a storm of immediate tactical tasks sucking up your attention. That's true for both software engineers (living in Jira tickets, sprints, and one-to-two quarter projects) and the c-suite.
These sessions can force you to make time, put aside the tactical noise, and think.
By continuous I mean end of year shouldn’t be to special, you could have a rolling plan and amend it every month with offsite when it is felt that brainpower is needed and especially more grassroots input is needed.
Usually these don't match the day to day near continuous work enough to be useful, but so it goes.