After some testing of labels:
There could be a temptation to “label” all your entities to have a possibility like “show all batteries related to a heating equipment in my south-west bathroom”.
I.e. this could be only for PRESENTATION - to show only THESE particular entities in a table.
It may cause having 100500 labels in the “filter” panel.
Next you may want to rename these labels to be ordered in a specific way (and starting questions like “WTH label_ids are not renamed after I renamed labels”).
You may want to have these labels hierarchically displayed - like “show 5 root labels, each label may have sub-labels etc”.
You may want to have persistent presets like described here - i.e. there will be no need to select a particular label out of 100500 labels, just select a “Bathroom heating batteries” preset.
For now I ended up keep using my “old style labels” which are defined in yaml and may only be used in templates to select entities, not to be used in UI in tables (except “Dev tools → State”).
“New style” labels will be added only when I really will need them to be used in UI tables for filtering; do not think there will be many of them.
As for replacing my “old style labels” by “new style” labels - will probably do it in SOME cases and only when a “yaml labels support” will be added. Why “SOME cases”, not “ALL cases” - because some labels may not be needed in UI (to avoid clutter in labels).