However, as you said, if the investor does not have enough funds to buy the DIP, in that case he can invest half of the money from his other funds, but he should replace the fund again as soon as possible.
But, this type of decision should be made only that situations, when the investor's long-term goal is clear, because if the investor's goal is to make short-term profits, then buying a Bitcoin DIP with emergency funds in such a way is never reasonable, because it will be trading, and as a result of this type of activity you will lose your important fund.
Therefore, when making such decisions, the investor must be responsible and maintain a long-term perspective, and also must replace the investment as soon as possible.
If you do not have enough funds to buy DIP, then I think it is better not to be attracted to DIP. As you said, half of the money from other funds can be used for a specific purpose for buying DIP. But I think emergency fund should not be aggressive in investing for any purpose or even a small part should be used for buying DIP. If you have any other funds outside the emergency fund, then you can consider them. But emergency fund is for emergency moments, making an exception to it may be a wrong move for you and I think buying DIP is not an emergency.
If you stay in investment for a long time, you will get the opportunity to buy DIP again and again. So if you do not have the funds to buy DIP, then it is better for you to leave that opportunity and the right step may be to plan to prepare yourself for the next DIP.
Although I am not completely proving your point wrong, you could have been a little clearer in your statement. You could have mentioned the emergency fund and said that you can take the opportunity to buy dips by using half of the funds other than the emergency fund and refill those funds later. Emergency funds should not be used for this reason, because you bought dips with half of the money from the emergency fund today, if the emergency arises tomorrow and half of the money in the fund is not enough, how will you take action then? It will be very difficult for you to take action then and you may be forced to take the wrong action.