«جاءني القوم حتى خالد»
The people came to me, even Khalid.
Here ḥattā (حتى) presents Khalid as an endpoint or a notably included participant. It is especially effective if his coming is surprising, marks the limit of the group, or completes an ascending or descending sequence.
“جاءني القوم وخالد” can simply coordinate another participant. It does not necessarily convey the special endpoint expressed by ḥattā.
The conjunction must fit the relevant relation. It cannot be attached mechanically to the last name in every enumeration.