If you have 'gains' --- that may be true. But that --- and 20-20 hind-sight --- don't change the REAL meanings of the words.
While you're in 'the heat of the battle', to "trade"/"invest" short-term or long-term can be a rough decision --- and to take "profits" now, rather than wait for an UN-certain 'future' can be "wise".
(Realizing that "long-term" for 'takeses' is OVER one year. So, again, 'long-term' for an "investor"/"trader" may be three months, six months, ..., but for 'takeses purposes' it's over one year.)
If your 'style' is to "trade"/"invest" over 24 - 72 hours --- rather than over 6+ months --- (or vice versa,) you're still BOTH a "trader"/"investor" under BOTH (and ALL other) scenarios. (Are you not!?)