To me it doesn't get any more bullish than the NYSE and the NASDAQ getting into bitcoin .
I think the downward spiral we are in is really hard to break out of cause the miners need to sell sell sell just to keep the damn lights on.
If we can get some real, good news that can kick start new buyers we can get out of this spiral and start building again. The news has been good, but the miners are using it up to sell asap.
I believe their investment was moreso into the btc infrastructure (coinbase). This way they make money regardless of price. This is why I dont think their investments are a bullish sign (not yet)