Stocking up is probably the best thing to do during this time that the market is in sideways because you have a discounted price for all the bircoin out there in the market. Plus it's a great filter for people who don't deserve to get a big profit because these times can make someone easily panic over the fact that the prices are going wild.
It really really does depend on what you are doing though. If you are holding or trading super long term then for sure, sideways is buying time, but not too much too or you got nothing left when the real dip happens. On the other hand, if you are a short termer then you keep wanting to make money from volatility even during sideways market periods.