Just saying BTC works surprisingly well to pay for goods and services. You can deposit/withdraw in BTC at FXOpen, Forex Metal, Lite Forex, and a few other brokers. Expect more brokers to accept bitcoin in the future.
But I only get BTC to make payments. Hoarding physical bitcoins is pointless and even dangerous. Read a story today how the FBI can seize bitcoins if they trace back to illegal activity -- even if you purchased them legally.
As for speculation, why ignore a 24/7 market totally uncorrelated to global economic data? Several brokers now offer bitcoin CFDs: FXOpen, Forex Metal, Avatrade, Plus500, FXChoice, eToro, Bit4x. I know FXOpen charges .25% round turn plus a couple dollar spread. Considering Bitcoin's volatility, that's not bad.