The charts can only tell us that it went up in the past. What interests most people more is if it will go up in the future.
"Past earnings do not guarantee future earnings" can be said of literally any investment.
It is already said of every investment, which is why siwatanejo's suggestion earlier that bitcoin would be a good investment right now based on historical charts is such an uninsightful comment.
Ah yes, I forgot, number goes up in the short (10 years) term is the necessary and sufficient condition for any good investment. /s
What chart should I look at to not feel like investment is a bad idea right now? Because looking at Google and the 5Y for BTC it seems stalled between 30 - 40 and has not gotten back to its peak of 60.
Good investments can't be looked in the short-term. Over the medium-term, bitcoin has been the best investment in history.