That's right. It is very perfect for everyone to enter the crypto market when the price of bitcoin and other top altcoins is low price, but it is not everyone that will enter the market at the same time. There will be some investors who will get to know about bitcoin at its bull run, they will like to invest because of what the future holds for bitcoin in this bull run. You wouldn't advise someone who have such goal of making profits in bitcoin for long term not to invest because they miss to invest in bitcoin at low price. Your advice will be for them to go on to invest in bitcoin, so long as they are investing with the money they can afford to lose and they have a long term investment plan.
That's right, if you don't want to accept higher risks, DCA can be done with money that is free from primary needs. Using money that you are ready to lose is safer than having to force yourself to get high profits but not being able to perfectly implement the correct trading strategy. In fact, it will only increase the risk in trading.
It is better for us to pay attention to allocations for investments that will never affect our main assets. So, for example, if we need money suddenly, the free money will not be touched and will not decrease. And also we can still survive.