That is correct!
As they get more complex like using multiple transclusions or macros that use macros it is good to have each macro respond to currentTiddler, rather than demand a tiddlername be provided.
To follow your example;
<<currentTiddler>>
<$list filter="[tag[HelloThere]]" variable=additional-tag>
:<<currentTiddler>> <<additional-tag>>
</$list>
<<currentTiddler>>
In which case <<currentTiddler>>
remains the original tiddler.
The final code pattern used here is when you don’t need the value of the filter.
<<currentTiddler>>
<$list filter="[all[current]tag[HelloThere]]" variable=nul>
:<<currentTiddler>>
</$list>
<<currentTiddler>>