The government has already proven itself to be untrustworthy, not sure what benefit people get out of giving them personal information about their age, income, etc. The IRS, DMV, social security, etc already has all the information they need. Saying it is important is like saying it is important to give out your information to Google to make it easier to cater search results and give you targeted advertisements.
Where to build specific medical facilities is based on age and population. A community of 25 year old heterosexuals is going to have kids, where a community of 85 year olds is going to have geriatric issues. It also impacts the needs for transportation etc.
Income adjusts where you have to subsidize local hospitals, where to place welfare offices etc.
As to why you need to collect this info again, homeless people don’t report income to the IRS etc.
> As to why you need to collect this info again, homeless people don’t report income to the IRS etc.
Many homeless people also do not have mail, so they never get contacted or participate in the census. If they are in a shelter, then that shelter already has their information.