Follow Pacun's explanation to get a grasp on crypto. IRS regs consider crypto to be property, subject to the usual cap gain/loss rules with the exception that wash sale rules don't apply; no FBAR reporting is required either at this time. (Not sure about a Venezuela registered account though.)
The FMV of the "rewards" is reported as other income, because the client got something of value for nothing (just like getting interest). I'd say the Venezuela freebie is also other income (just like banks used to offer you $20 to open an account), again because you got something for nothing.
Crypto purchases are not tax reportable (just like buying stock isn't; IRS even says not to mark the box on the return if the client only bought crypto). Sales, however, are capital transactions. Conversion is selling one type of coin to buy another (just like selling GM stock to buy Ford stock), so it goes on Sch D. Using a coin to pay for something is also a sale, but hardly anyone ever does that. Moving coins from one wallet or exchange to another is not reportable, just like changing banks doesn't have any tax implications. Just think of the coins as stock. If you buy it, nothing to report. If you sell, it goes on Sch D.
Tell crypto clients to get the tracking software. My clients who have it produce a filled in Sch D complete with 8949s, which I attach to the return. Coinbase statements often don't give dates and even if they did, the prices of various cryptos change by the second so there is no way to look up FMV like you could for a stock. The software may also account for things like "hard forks" and "airdrops" that I won't confuse you with because I'm confused! The basic rubric, though, is treat it like a stock transaction--that should make it simpler in your mind and eliminate most of the noise.