when you have a good backup fund and steady cash flow it is important becuase it keeps one grounded during unpredictable market moves when making sure to time the market perfectly sometimes it backfires , waiting for dip can lead to missed opportunities. letting some things play out naturally while staying prepared is rightly the smart way to approach investing.
Why quoting the whole post? It would be better that you picked the part the post that you are talking about that's by the way, am kind of wondering what does having a good backup funds and a steady cash flow has to do with keeping one grounded during market fluctuations? That is more like a traders mentality, because as an investor having a good backup funds and a steady cash flow will only put you in the position of taken advantage of any conditions of the market fluctuations, the market remains unpredictable and no one can be certain about timing the market.