As BTC has gained over 100% this year, most observers tied its recent strength to a looming approval of a spot BTC ETF. But its increasingly constrained supply, underinvested market participants and bitcoin’s rejuvenated shine as a safe haven from spiraling debt levels, banking crises and geopolitical turmoil may also have played a role.Read MoreCoinDesk: Bitcoin, Ethereum, Crypto News and Price Data[#item_full_content]