Why is Hawaii the only state with that information provided?
The canvass breaks them out by congressional district (59 1st CD, 20 2nd CD, and 1 presidential), so there apparently is an address of the former residence associated with them.
Since some overseas voters are limited to federal contests only (President, US Senator, and US Representative) it may not be practical to tie them to a voting precinct. Given the small number of overseas voters, there are probably privacy concerns in accounting for their vote by precinct.
If all the other votes are by precinct it is a simple matter to accumulate the precinct totals for each individual race and each subtotal. The federal overseas votes could then simply be added into the final totals. In the canvass that is online, the overseas votes are not broken out by candidate., there is simply an accounting of the total number of such votes. The candidate breakdown can be inferred from the Hawaii-wide and county-wide results.
Also, Hawaii, in general has a more centralized government than most other states. In most states, elections are conducted by county or town governments. If Hawaii elections are conducted by the state government, then county results would be more matters of accounting.
