I welcome Pacific Islanders. There is about 3 million people in Micronesia, Polynesia, and Melanesia, and maybe half of them are living on these kinds of marginal atolls.
There are 7.3 million people in Papua New Guinea alone—almost 10 million in Melanesia altogether. Happily, most of them live on volcanic islands which won't be as severely affected by sea level rise. Although, for the record, Vanuatu (where I live) was hit by a record-setting cyclone in March, and is currently enduring drought induced by the worst El Niño in recorded history.
Anyway, far less than half of all Pacific islanders live on low-lying atolls. The population of Kiribati is just over 100,000. Tuvalu is a mere 10,000, Federated States of Micronesia is about 100,000, and the Marshalls are just 52,000.
If the measure of their importance is simply counting lives, these places don't matter much.
But if the measure of importance is that they're the proverbial canary in the coal mine (sorry), then yeah, they kind of matter. And how we treat them is going to set a precedent for how we treat the hundreds of millions who will quickly follow—most of whom are likely to be domestic climate refugees.