For an investor who is investing in bitcoin for the long term and has $90 as discretionary income, it is wrong for that investor to only use $10 to accumulate bitcoin with the DCA strategy and keep $80 to buy the dip that he is not even certain will happen. In my opinion, I would even advise such an investor to use $80 in accumulating bitcoin with the DCA strategy consistently and reserve $10 in his reserve fund so that he can use it and buy the dip anytime it happens, which will help him to accumulate a reasonable bitcoin faster using the DCA strategy while he still waits for the dip with the $10 he is reserving in his reserve fund weekly or monthly.
I'm with your motion on this because if the discussion was about his salary ratios and how $10 investment will be okay for him then it wouldn't be disagreeable because him alone knows what he can afford on Bitcoin but on the contrary this is a case of discretionary income which importance is not too serious that if 50 percent is removed for investment something will happen to his other live, so actually I cannot have $90 discretionary and use only $10 for investment hopping for God knows when the time the market will tell them to buy, though I wouldn't buy with all the $90 but definitely $60 will be use.