Quill is a skilled fighter trained in both hand-to-hand combat and the use of advanced weaponry. His experience in battles against formidable foes like Ronan the Accuser and Thanos adds to his combat expertise. This versatility and experience make him a formidable ally in the Avengers' battles against powerful enemies.

Strategic Mind

Quill often demonstrates a knack for strategy and improvisation, which can be crucial in battles against powerful enemies. His ability to think on his feet and adapt to changing situations makes him a valuable asset to the Avengers.

Connection to Cosmic Threats

Quill has firsthand experience dealing with cosmic-level threats, making him invaluable to the Avengers. His knowledge and experience with intergalactic villains such as Thanos can be crucial in facing such threats.

Cultural Insight

As a human raised in space, Quill has a unique perspective and understanding of various alien cultures. This cultural insight can aid the Avengers in negotiations or conflicts involving extraterrestrial entities, making him a valuable team member.

Humor and Morale

Quill’s sense of humor and charisma can help boost team morale, especially during tough missions. His ability to keep the team in good spirits is a significant asset that often helps the team overcome challenges and keeps their spirits high.

While he may not have the same level of power as some Avengers, Quill's skills, experience, and personality can contribute significantly to the team's dynamics and effectiveness. However, it is not just his personal qualities that make him valuable to the Avengers; it is also because he is the only leader the Guardians of the Galaxy respect enough to follow.

The Guardians aren't the brightest bunch for the most part. They are insubordinate, clumsy, and often cocky. To most people, they are more of a nuisance than helpful. But as a team, they make it work. They have saved the Galaxy twice, and each time they battled against even the mighty Thanos. Each of these times, they rallied behind their leader: Peter Quill.

They follow Quill not because he is flawless but rather because he is flawed. They see similarities between themselves and him. They pledged their allegiance to him because, in some ways, he was the most misfit of all. Quill has screwed up, he’s emotional, and at times, unhinged. But that’s why the Guardians follow him. Sometimes those emotions get the better of him, but he is the best chance for getting the Guardians of the Galaxy to fight alongside the Avengers.

In conclusion, Peter Quill brings unique assets to the Avengers. His leadership, combat skills, strategic mindset, and cultural insight, combined with his ability to boost team morale, make him an invaluable member of the team despite his unconventional background.