So the vision is the goal and the strategy is the plan to get there. Why should you care? Because everything about the company depends on the vision and strategy. If the company's vision is to be 'the world's lowest cost provider of doodads, then strategies have to be put in place to single mindedly cut costs from the development, production, and delivery of doodads. That doesn't mean that the company itself can't spend a lot of money achieving its vision. Maybe they have a huge R&D department dedicated to finding ways to make cheaper doodads. But it does mean that if you, as an employee, come up with way to make an improved doodad with more features, it will be considered 'off-strategy'. The vision isn't to make better doodads, and it isn't to make them higher quality, or last longer. Build a cheaper doodad and you'll be a hero. That's what matters.
(Aside: strategy is often about what NOT to do. One of my favorite Dilbert cartoons has a panel called 'Before Strategy'. In it, Dilbert is one the phone saying "I don't know if we do that." In the next panel, 'After Strategy', Dilbert is on the phone saying "We don't do that." You get the idea.)
What's important to you is that you know and understand the vision and strategy and live it. It's not helpful to make decisions or suggestions that aren't consistent with the strategy. Strategy can, and usually does, impose constraints. One of my friends relates a story from a startup that was building a chip which had to be of a certain size, which dictates the number of transistors you can put on it. The junior engineers kept suggesting improvements and additions to the functionality which would require more than the maximum number of transistors. They were all good suggestions - and a total waste of time. Unless the engineers could also show how the improvements could be implemented within the constraints of the chip size, it didn't matter how good the suggestions were.
You may not agree with the strategy, but you'll have to live with it until it changes.