Although we don't know for sure the impact on Bitcoin, one thing is sure: developed economies are stagnating and the pace of innovation is decreasing.
Negative interest rates are a form of nudge to stimulate investment, pushing towards higher risk and higher return, instead of negative yields.
BTC and other cryptos are not correlated with the performance of traditional financial assets, making it a possible attractive investment for a diversification strategy.
It can serve as a safe asset that cannot be seized, which is a key features in a multi-lateral world in turmoil (trade wars, proxy wars, sanctions).
Since BTC is decentralized and not bound to the performance of a specific economy, it's likely to be more appealing than ever.