Inverse funds appeal because they need no margin account, no borrow, and carry no unlimited loss. The cost is the same daily reset as a leveraged-etf: the position is rebalanced each night, so multi-day returns depend on path and not just on direction.
There is also a structural drift. Equity indices rise over long periods and the funds pay financing and fees, so an inverse fund held indefinitely trends toward zero even ignoring volatility-decay. Treat them as short-dated hedges, not as a way to stay short.
Example: an index falls 20% over a year but does so through repeated 4% swings. A -1x fund returns 14% rather than 20%, and a -2x fund returns 24% rather than 40%, with the gap lost to daily resets.
Related: leveraged-etf, volatility-decay, short-selling, etf, hedge