From the scenario you cited out, it shows that a bitcoin investor has to have a steady source of income for a healthy bitcoin investment. Its not all about having the initial amount to start with, what if you run into problems that will require you to make withdrawals because there are no other source of income. I hear some people say "borrow to invest" one can only borrow to invest if you already have a guaranteed source of paying back without considering your investment. The fear of missing out on the dip can make an investor borrow in other to take advantage of that opportunity but he should have the capacity to pay back without intervening his investment. The reason I picked DCA above every other strategy is because, it is applicable to all market trend. At pump, dump or sideways one can make investment without considering the market price and will end up with profits if patience is exercised.
No, in my opinion you should not invest with debt. Because it may happen that you have invested with loan and failure to repay the loan can affect your investment. So you set a budget from each month's income and invest according to that budget on a weekly or monthly basis using the DCA method. You don't need to take a loan to buy a dip, if you invest in the DCA method you can buy bitcoins at more or less average prices. We should not rush to invest, we should plan long-term investment. To be successful in bitcoin you need to continue investing in long term DCA method, if you can continue DCA for long 8-10 years then no need to borrow, you will be able to buy dip if you continue DCA.