Investing in Bitcoin is always a smart thing, in my opinion. Because you are not able to know when the price will reach the highest level of its potential and start going down sharply. There are many people and companies that still prefer continuing to buy. And I don't think it will change easily at whatever level we see the price.
Smarter thing to do when investing in bitcoin is knowing when to get in to maximize profits overtime, for example you enter at around the current price then the next day the prices slumped down significantly but if you waited for that to happen then you could've got a cheaper entrance to bitcoin, always enter the bitcoin market when the prices are going down because overtime it will go up.
I think the smartest strategy is to take entry and exit decision based on signals generated by Technical charts. That is the best way to maximize profit and minimize risk because charts reflect the sentiments of market participants. Thought it is not perfect science as it is based on probabilities and Historical data but this is the best tool that is used by most of Professional and Institutional Investors.