Quick reply
"Hello Andre,
Thanks for the note.
Regarding the statement that you have referenced, I was simply suggesting that one should not completely abandon outdoor conditioning methods (ex. interval training). Indoor alternatives are useful, but should not mean the end of all outdoor conditioning drills. For example, hill sprints and interval running still have a place (although are not always possible due to poor weather).
Ultimately, variety is the key, regardless of the modality.
Best of luck,
Ross"