Holding really matters in investing in Bitcoin but it doesn't mean we have to do this our whole life. If we take a look at the price chart, prices are growing but can we think this will be the same trend in the next few years? Not for sure and it was uncertain. So I could say that holding will not be forever as it also depends on the market situation. Selling our Bitcoin during the bull season is a perfect option IMHO and get on the train back again once the market correction starts. But yes, this needs strong hands because waiting for 4 years is not as easy as people think as we need to deal our emotions as well.
Investors that have the experience and that had been holding for a long time could attest that it pays to hold but that might not be easy for everyone that is a Bitcoin investor. It takes courage for us to keep seeing our holding losing value continuously without knowing whether to sell to keep the remaining lost or to keep holding.
Although not all holdings are profitable so we need to know what we are doing so that we don't invest our funds in a bad project that will not make us to finally lose our funds. This is why Bitcoin is the only project in the crypto market that can give us what will want although the risk is also there for us to choose whether to be a long term holders or short term holders.