Here is my investment strategy in regards to coins... digital and physical. I may be the most ignorant investor in the World but I'm having some good results.
For fun (maybe $100 investment). Go to liquid.io and buy the big loser for the day. Wait a few days and usually it becomes the big winner. I don't know why and don't try it on some of the bigger exchanges. As of writing this it would be PRO which is down 9%. Crypto is having a pretty good day so you might hold it for a week but I'm betting it will be on the other side before playoff baseball.
Don't hold much BTC, ETH or LTC. These are really the Big 3 and if you are holding Apple, Google and Amazon I would drop those also. All of these assets are currently over valued and in a bubble but if BTC dropped under $2000 I would take a second out on my home and buy.
Don't get greedy and don't turn your back on them. I have a friend holding $30K in BTC and just wants to forget about it for 5 years. There are too many unknowns (especially in the US) to ignore your portfolio and simply expect it to be worth 500X the current value. Also, you miss the opportunities to cash out a little bit at a time.
Set realistic price goals for your big 3. This week I had buys in for BTC at $3500 and LTC at $42. I started selling both earlier today. I never cash out in USD but instead buy silver and gold with 60% (70/30 new and numismatic and only $5 gold coins if they are under $170). 35% I use to buy some of the under valued coins like NEO, GAS, OMG and always add to your XRP and STEEM. The last 5% I throw some into liquid.io (as I mentioned before) and then I'll grab some odd ones like RDD. This is more for fun and to keep things in perspective. RDD went up 50% today and I made a whopping $9 and I expect it to go back down tonight (but you never know).
When your silver and gold coins arrive always weigh them and verify the dimensions. Hold them and enjoy them. I give some to my kids and they look perplexed. I think they somehow comprehend the value. I've read some crazy articles about gold and silver becoming genetically linked to value because of thousands of years of value but who knows. I do see them drop dollar bills and forget about them or throw $40 towards some stupid Xbox game that gets lost a week later.
Also, be a picky coin buyer. There are deals to be found on purse.io. If buying while BTC is high, I usually look for Morgan dollars. I bought a set of 20 for $380 with tax and shipping. By the time they arrived and BTC was around $3400 the cost per coin was below the spot price. If BTC is sagging a bit, I buy bars or Liberty dollars (mostly from APMEX). Don't be upset if you buy something for $200 and see it the next day for $175. Remember that you are trading worthless fiat for digital coins and taking your profits to grab real money. It always makes me smile.
The dichotomy is what fascinates me. In the end, I plan to be 50/50 in crypto coins and physical. Half is something that has held its value since B.C. years and half is so new that 90% of the sheep out there know nothing about it.
FYI.... I own zero gold or silver stocks. Don't trust Wallstreet and never will.