Many people might want to hold nano longer term as demand grows and supply is limited. However fortunately there are no direct financial rewards for holding nano as opposed to proof of stake currencies.
The Nano Foundation doesn't have a massive marketing budget. Nano does only one thing, and that one thing directly competes with Bitcoin. In the short term it's going to be very difficult for Nano.
In addition to their own cryptocurrency, XRP, Ripple's network can transfer other cryptocurrencies such as Bitcoin, fiat currencies, gold, IOUs, frequent flyer miles and so on.
In order to remain anonymous you must utilize a set of keys set by a group of individuals. If it got cracked or somehow leaked or if this group was corrupt your transactions might not be anonymous.
There is discussion to change this: https://www.starkware.co/
More Info: https://www.reddit.com/r/zec/comments/551wnw/what_is_the_trusted_setup_in_zcash_an_overview/
It takes on average 10 minutes for a block to be added to the blockchain. You may want to wait for multiple blocks to be added to the blockchain to be sure that there's no tampering happening with the blockchain. The usual recommendation for larger transactions is to wait for 6 blocks before confirming the transaction which comes down to an hour on average.