there is lots of debate going on about the future of deflationary coins but one thing is very clear now after seeing the behavior of BOOM that deflationary tokens are here to stay. Its better to keep an eye on them to book your future profit.
We cant say this with certainty. If you see price chart of BOOM on CMC then its evident that there are only two spikes in last 3 months and since then price is continuously going down. You may invest some of your money in deflationary coins like BOOM but there are visible chances that your investment may hang up for a long time. DYOR before u make any decision.