Which is your most concern? Keeping your Bitcoin safe or cheapest way of swapping your Bitcoin into altcoins?
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I tend to agree above, incognito wallet is quite a new Bitcoin wallet and it seems it needs more improvement. For swapping purposes, $10-15 still quite high, it might the same rate in Coinomi wallet which is the oldest wallet compared to this.
Sometimes when you are trading a very low volume, such as 20-100 USD, it is cheaper, faster and more private to use a swaping service. I have used a lot. I used all of them, inside coinomi app and out, from shapeshift to easyrabbit (lol, i don't even know if they still exist).
Swapping services are sometimes good to use because they don't have withdrawal fees. But when you are using a higher volume, they become expensive.
This wallet might be ok if you are using just a few bucks in it, but I wouldn't trust a lot of money in it.
Also, it is better to trade in an exhcange if you have more than 1000 USD, maybe even less depending on the coin and exchange. Probably FTX is much cheaper, as they have no withdrawal fees for most coins.