Figure out your bitcoin plan first, and then maybe if you have accumulated a decent amount of bitcoin, then maybe at some point it might become justifiable to diversify, but talking about diversification into gold and/or silver makes it sound like you are pumping inferior products and trying to compare them to bitcoin when bitcoin is likely in the ballpark of 1000x better then each of them...so no need to discuss any particulars of them or to pump them, especially here in this thread when we are talking about bitcoin.
About the idea of diversifying into several forms of investment and it's not much better than trying to make a percentage purchase of bitcoin. In the past, I was one of the people who bought gold to save and the price movement was not much better even though I had kept it for more than five years. Finally I decided to buy bitcoin as an investment asset that I held and the comparison in the same five years was much more favorable to bitcoin. Regarding the risk that is often talked about and I think it really depends on our mental readiness, if bitcoin is bought and held then it should not be part of short-term trading so we will not experience any risk.
I am new to buying bitcoin to hold without being in a rush to sell and I can already agree with you on the risk not being significant for holding bitcoin for long. I know the fear and anxiety I was facing being a short term trader, it was draining me psychologically and most times I will sell and within few days regret why I sold so fast. The same with buying only to see the price go lower with a few days and I will be angry that I would have waited more. The possibilities of making mistakes with short time investment in bitcoin is just so high. Now I fell a bit relaxed and comfortable with bitcoin and even the spikes that do happen no longer bother me anymore. I don't even notice most of them because I no longer check the chat often unless when my money to purchase is ready, then I can look at the market and make an entry.