Investment in banks, gold and other assets and channels are good, only that the risk involved varies. The gold you are talking about could be a bad investment if the person did that carelessly, this also goes for Bitcoin. That is why one should know what they are signing for to invest the right way, and this is why I advise people to note that the previous performance of an investment is not a guarantee of their future success despite the track record of assets giving multiplies of returns in the past.
A bank is another good alternative, the return might be lower but the return on the investment is much more guaranteed unless the bank liquidates without insurance which is rare these days.
Also, I found it strange that banks buy your gold cheaply and sell it expensive, Do you mean in this open era? That is impossible unless you get yourself duped. All assets have their prevailing listing prices with their Bid and Ask tagged well to them. No one can cheat you and it is not necessary for you to sell your assets to a bank, you have diverse alternatives.
Money will always depreciate by the time, the longer you keep it the lesser the value will be. The amount of money that you will have right now will have lesser value if you use it next year. So investing in gold is better, because good price will always increase, especially if there is a problem on global or national economic crisis. Gold if it is easily sellable and the premium is reasonable is not a bad choice of investment, currently we are facing inflation and it’s a world problem. Fiats are growing weak due to the world challenges, which is why gold is a better alternative to save and it will appreciate with time.
I would tell you to use the U.S dollars if you aren’t facing circumstances such as daily exchange limits.if you are in the U.S dollar, then silver are accessible as a hedge. Silver was a higher appreciating asset in the 2008 recession not many invest in this asset cause of lack of idea on the actual cost value of the asset. In Nigeria currently due to the economic crisis of the country makes the U.S dollar a very good deal. You can save up in dollars and be rest assured you will get a decent return on your money. Dollars are great for short term investment option.