Why did Robert Grant believe a presence of armed steamships was important?

Robert Grant believed that the presence of armed steamships was crucial for helping to secure British interests in the area due to the strategic and economic implications of naval power. Armed steamships provided not only military security but also enhanced the ability to protect trade routes and commerce against potential threats. At a time when imperial interests were often contested, having a naval presence allowed Britain to project power and maintain influence in various regions. This capability was essential for both defense and to ensure that British interests, such as trade or territorial claims, were safeguarded.

In the context of the other options, while tourism, scientific research, and humanitarian efforts could benefit from improved maritime capabilities, they were not the primary motivations for Grant's emphasis on armed steamships. Instead, he focused on their role in promoting national security and protecting economic interests, which were paramount in the geopolitics of the era.