There could be several reasons why many hesitate to invest, but like you said above, investment is basically a choice.
You are pretty right most people are skeptical about Bitcoin investment probably due to speculation from friends and family or social media which make them have that negative inception in them and always make them think awkward about bitcoin. According to my research I was made do understand that why many people are afraid of investing in bitcoin is as follows:
1. Extreme volatility
2. Neither commodity, nor currency
3. Don’t invest if you don’t understand
4. An unregulated space
5. The issue of legality
6. Ponzi schemes abound
7. Prone to illegal activity
You can click on this
link here, for the full explanation
But however, this factors does not implies that one should not hold on to Bitcoin. Or invest on it. I see this factors listed above as a deceptive factor and a speculation due to misinformation and lack of Doing proper research. Lack of focus with negative mindset Leeds to misconception. Despite most of them are true, but we should always take advantage of the important part of it rather than sticking to the negative aspect. Everything that has advantage also has disadvantages but the advantages should not be underestimated. Just buy and hold is the way and nothing else.
Another factor I think is that many persons are still very ill informed about bitcoin as a digital currency and asset especially the normal 30-40 year old that grew up in a time when fait was just reaching its peack and physical assets like land and gold where still the best investment you could engage in. And those who have idea of have have heard little about it are either still concerned about how it works and probably want to rely on someone to teach them about it instead of doing their own research about it and even if they want to wouldn't know where to start.
But with bitcoin ETF I guess this problem has been solved since trusted companies like Blackrock has now bridged the gap between having so much knowledge about bitcoin and investing in it. So if anyone still doesn't invest in bitcoin, it's now a thign of faith in the asset and as @Justbillywitt said requires motivation from 3rd party to engage in bitcoin investment.
Before deciding to hold maybe you should set some timeline on when you want to sell your stored asset so that you have something plan to hold and you will not get dismantle if you see something bearish situation in the market since it could possibly bother you.
This is not a very good advice to give newbies, cause they could start to develop a short term investment mentality from this, and I believe that our goal here is to hold BYC not to sell it to make profits, and we have talked about this kind of practice from time to time here as been very risk6and could lead to regret expecially when they sell with hopes of acquiring more BTC which no different from gambling with their holdings.
I think what you have meant to say is, its good to have a time frame to accumulate bitcoin, and we have said that a good time frame for a minimum should be at least 5 years of holding.