Lyn Alden: US deficit is a 'train you can't stop', bitcoin and gold to benefit

• —Alden says the US deficit is largely locked in and now a macro variable for investors
• —US debt has topped 100% of GDP, with interest costs a key driver of the deficit
• —The Fed is 'in the back seat' with deficits at 7% of GDP limiting monetary policy
• —Alden is long-term bullish on bitcoin and gold, but flags BTC's smaller size and higher volatility