There are three main reasons why endorsing our Delegate is important:

Regional security
In NationStates, the World Assembly Delegate of a region is the nation that has received the most endorsements from their regionmates. Most of the largest regions in the game, including 10000 Islands, have effectively replaced this system by one in which the Delegate is chosen through a more organized method (in our case, democratic elections held every 6 months). To enforce this system, the Delegate needs to receive the maximum endorsements possible while all other nations have their endorsement count limited (something known as an endorsement cap).

However, mechanically, in the eyes of the game itself, the Delegate is still simply the nation with the most endorsements, no matter how these endorsements where gathered. This can be exploited by other regions, commonly known as raiders, to irregularly seize the Delegacy by flooding the region with foreign nations that coordinately endorse each other.

As a fairly large and powerful region that is well known for opposing raiders all over NationStates (more below), 10000 Islands would make for a high-profile target. Precisely because of it, our region has taken care to be as secure as possible. 10000 Islands has a non-executive Delegate, which limits the damage that a potential raider invasion could have, as well as an active Founder, who can immediately undo any actions raiders can take in our region.

These security measures mean that 10000 Islands can never be really destroyed completely in an invasion. Regardless, rival regions still have an interest in temporarily securing the Delegate seat to embarrass us, and it is better in all cases if raiders fail to seize the Delegate position in the first place. While 10000 Islands is a very large region in which the Delegate typically has hundreds of endorsements, every single extra endorsement our WA Delegate has is one extra endorsement that raiders would need to overcome to overthrow the legitimate Delegate.

World Assembly voting power
WA Delegates are intended to represent their region's voice at the World Assembly. As such, they have special voting powers. The vote a Delegate casts is worth 1 + the number of endorsements they have. For this reason, powerful Delegates with very large votes tend to decide the outcome of a resolution. The more endorsements our Delegate has, the more powerful will 10000 Islands be at the World Assembly, allowing us to advance our interests and influence debates on new international law, Commendations, and Condemnations (which can be important to counter raider propaganda). Furthermore, in 10000 Islands, the Delegate's voice is your voice: the Delegate votes according to the result of a forum WA voting poll in which you can participate!

Advocating defender values
But a powerful WA vote is important not only for roleplay, but also to advocate our defender values. To our very core, 10000 Islands is a defender region that opposes raiders all over NationStates. Even for nations that are not directly involved with TITO, our regional army, 10000 Islands's stated political purpose at every level is to protect the safety of smaller, innocent regions that did not ask to be part of the NationStates' "raider and defender" (R&D) gameplay. If raiders succeed in invading a region and taking full control of it, its community is at a very high risk of being destroyed.

TITO is our region's main way of combating raiders. However, in some situations, raiders can get a strategic leg up in an invasion. In that case, there is still hope to save the community of the region being raided: a World Assembly Security Council Liberation Resolution. A SC Liberation forcibly removes the password of a region, allowing native nations to regain control with TITO's aid.

For this to occur though, the SC Liberation needs to pass at the World Assembly (with >50% support) as soon as possible, reason why a stronger vote at the World Assembly is absolutely crucial. We need to make sure our WA vote is at its absolute strongest to preserve the sovereignty of defenseless regions.