Just go back to September/October last year. Turned green, then red again for 2 weeks. Similar in December 2012.
That said, in the entire history of Bitcoin trading I know (which means including mtgox data), whenever the 1w MACD turned green there was never a drastic and lasting price decline.
The "worst" signal I can find is in the last December week in 2011. MACD turns green, if you wouldn't have waited for a period close you might have bought at slightly below $5. The rally continued to $7, then price fell sharply. Took another ~2 months before $5 was reached again.
Sounds like a fantastic opportunity in retrospect, of course (buying coins at $5), but from a trader's perspective, that wasn't a very good signal, unless you got out at the $7 peak.
Well, I think that your remarks make a lot of sense but, as you wrote, they mostly refer to a trader point of view (I hope I'm not misunderstanding your words).
At the end of day, what I'm trying to understand is only if we can
really consider the bear market ended (for medium and maybe long term).
To be more precise, I wonder if a stable green 1W MACD could be seen as a clear and unequivocal signal of reversal trend. I would say yes, but I'm not a TA expert, I'm just reading something about it and playing with charts.
But there is this consideration from you that is pretty reassuring:
whenever the 1w MACD turned green there was never a drastic and lasting price decline.