Bitcoin is the coin most people already hold and the one that records the most. Both of those facts matter, and which one dominates depends entirely on what the payment is for.
What it records
Every transaction writes the amount, the sending address and the receiving address to a ledger anybody can read, permanently. This is not a flaw, it is what the design does, and an entire analysis industry exists to walk those records back to people. Payments made years ago are still sitting there and still readable.
Timing
Blocks land roughly every ten minutes, and a market waiting for several confirmations means twenty minutes to an hour before an order shows as funded. During busy periods a transaction with a low fee can wait considerably longer, which is the most common reason a Bitcoin deposit appears slow.
Fees
Bitcoin fees float with demand rather than being fixed. A fee that was generous last week can be too low today, and a stuck transaction is stuck until the mempool clears or you replace it. Set the fee from your wallet current estimate rather than a habitual number.
When this is reasonable
When you already hold Bitcoin, understand that the payment is publicly recorded, and have decided that is acceptable for this purchase. What is not reasonable is choosing it by default because it was preselected, since the record it produces outlasts every other decision in the order.
Wallets
Electrum is the practical desktop choice and can be pointed through Tor. Avoid holding the coin on an exchange until the moment you spend it, since that is custody by somebody else under your verified identity.
Verified addresses
anubisqdpukalgiyxlb7rtcya3u6grun2mcozonmb57c54qrt7sqh7qd.onionanubisqe2yramasw5yvlnipaknraza5rzb5uxb7zqhxuxroobvvm6aid.onionanubisqocgruji655mqys7fpafawiy2g56pjqrtecfdikhh5q4zqmfqd.onionBefore you sign in. Open these in Tor Browser only, then compare the onion printed on the login screen against your browser address bar. If they do not match, close the tab.