Bull market is time for selling since it is the time where the market is booming and the Bitcoin price is surging. It is advisable to buy when the market is surging except when we had timed it at the beginning of it surging trend. While bear market is the phase for accumulation since the Bitcoin price during this time is getting tanked and dumped. I think these two trends balance each other and there both trend as as special. If I have the holdings, I would love to see Bitcoin to be in an uptrend or bull run while when I do not have, I would love it at a cheaper price so that I can buy BTC at a discount meaning buyer prefers BTC in bear market.
Nobody would prefer buying Bitcoin in the bull market because the price of Bitcoin would be very high, every individual wishes they can buy Bitcoin when the prices is low but not every individual can buy because money isn't always available to them at this times the market is low. Only those that planned for the low markets will succeed in buying Bitcoin. Which is why we have to plan during the bear market to buy by always reserving money by not spending them but saving.
If we missed buying during the bear market then we'll be those buying from those who are selling their Bitcoin for profit and we'll be left to hold through another bear market and hope that the price recovers as it always does when the bull market returns in another four years time.