The logic for investment is buying low and selling high and currently Bitcoin has a new ATHs is it safe to encourage new investor to buy now seeing how high the price has gone? My fear for new investors is that the don't experience a dip after buying since no one is sure of how far the new highs will reach.
Do not encourage anyone to buy if you are still hesitant to do it yourself. The logic is correct that buy dips and sell high, but this is a trade you can recommend for beginners who are new to bitcoin. If they are investors then they will just focus more on getting long term profit where they may not really care about the bitcoin price when they want to buy it.
We are not responsible for encouraging anyone to get involved in this investment. If someone ask for your advice then it is better if you also tell them about the risk of this investment which is not only about price volatility but also security risks lurking.