You get extra yield immediatelly and get access to this resource, if you have the tech, but you cant later get benefit of additional yield from improvement on resource.Is founding cities on resources beneficial, and does VP change anything about it? Do I get bonuses from buildings?
For example if you move on some luxury that has +1 gold, you get +1 gold from turn 1, which is a head start. But you lose access later to for example +1 culture, if it was gold, since
you cant build a mine on it any more.. I almost never do it, but saw some playtrougs on diety, ppl actually do this.
If building say, you have +x from resource then yes, if it say from specific improvement specific resource, then not.
Basically wording is accurate, unless there is a bug

As fare i know, depending on implementation, sometimes those yields can show on building itselve, and sometimes on city square as a "bonus from terrian",
same way as science from artistry policies is added to city square, and not for example to palace yields. That might be confusing sometimes.