Text objects have a default placement that you can set in Engraving Options > Text, like other notation items. They’re not aligned with barlines like rehearsal marks are no, but they should be consistently positioned relative to their rhythmic position and other items around them, if they have collision avoidance turned on. If you graphically offset one and copy/paste it, the offset will be applied in relation to the default position rather than in absolute values from the staff - so you if you copy it to a place with lots of other notations and the text is automatically avoiding collisions, it could well end up positioned differently. You can also turn collision avoidance off and position them manually - that might end up with more consistent positioning if you copy/paste text items, but I confess I’ve not tested that rigorously.
If you like rehearsal marks for this, absolutely just go ahead! I only really mentioned this because some users use rehearsal marks as a way of getting bordered text (so they change the index for the rehearsal mark to the first letter they want in the word, like Chorus) but now you can have paragraph styles bordered by default, that might be a better way long-term.