What happens if BTC dominance goes down?

What was the lowest Bitcoin dominance in December 2017?

Bitcoin dominance breaks down In just 5 weeks—between December 4, 2017, and January 8, 2018—it dropped from 71% to 35.5% .

When BTC Dominance goes up, alts, on the whole, lose value against BTC. When BTC Dominance goes down, alts on the whole, gain value vs BTC .