Everyone feels good when BTC prices are at all time highs, so part of the reason that I frequently suggest getting through a whole cycle or two, because sometimes even the best of practices may end up having extended periods of being in the negative (on paper), and so some guys might get discouraged by their BTC being in the negative, and sometimes the period of being in the negative could end up lasting a couple of years or longer...of course personal details regarding timing (when he got in) can also make differences, too.
I totally agree with you because even with the best or right investment strategy, there maybe a time where your expectations may not be met and your portfolios are all on red, therefore having a long term perspective is simply the best approach towards achieving your goal with Bitcoin, as the market is unpredictable.
Newcomers should be aware of this so as to not make emotional decisions in regards to short-term market fluctuations.
Furthermore , going for a whole cycle or two would give the investors an insight about the market dynamics and further help them develop the patient which is required to navigate through and in times of those market volatility.