Velocity is used to predict how much work a team can complete in the future, based on their performance in the past. This can be helpful for teams to understand their own capabilities and for stakeholders to understand how much work can be accomplished within a certain timeframe. For example, with a velocity of 25 they know how to gauge the number of Story Points that they will take into the sprint. However, the team will only get a real sense of how much work they can do in the next sprint once they break up the stories into smaller tasks. Their velocity will guide them as to how much work they will take on.
However, it's important to note that velocity is not meant to be a strict target or quota for a team to meet.
The Scrum framework encourages teams to commit to a certain amount of work in each sprint based on their own capacity and capabilities. This commitment is made during the sprint planning process, where the team reviews the backlog of work and decides what can reasonably be completed within the sprint. The team's velocity is taken into consideration when making this commitment, but it is not the sole determining factor.
So to answer the question of whether Scrum teams' commitments are influenced by velocity, the answer is both yes and no. Velocity is one factor that is considered when a team makes a commitment, but it is not the only factor. Other factors that may influence a team's commitment include the complexity of the work, the team's current workload and capacity, and the availability of resources.
It's important for Scrum teams to understand the role of velocity in their process and use it as a tool to help predict and plan their work, rather than as a strict target to meet. By considering a range of factors when making commitments, Scrum teams can more accurately set expectations and deliver value to stakeholders.