The risk in long term bitcoin is very low, but I think a person should not over invest in bitcoin. Bitcoin is the ideal investment area to invest in. Just because it's long, doesn't mean you should invest all your money in Bitcoin. Such investments are likely to incur losses.
Every business in the world is risk associated and if you earn profit you have to take risks, these risks will make you millionaires or billionaires. So with bitcoin both short term and long term investments are profitable only when you done market analysis before investing the capital amount. It usually depends on your capital amount, if your capital amount is above 100k US dollars then go for short term trading you can easily earn between 1200$ to 1650$ weekly or after 3-4 days as the price is fluctuates daily.