that is not a risk because there are ways of solving the problem if you paid a lower fee than you should have and had your transaction stuck. and Electrum and Bitcoin core are already marking the transactions as RBF by default which makes that easy to solve.
I mean, when you buy bitcoins (
from an exchange in this case) in some cases you don't have an option to choose the tx fee of the withdrawal request.
If this was from December, when you directly use the invoice deposit address from the mixer (
Buy Bitcoins -> Send to Mixer -> Your Wallet) and it didn't make it in time, that's the risk (
for a newbie like OP).
But as I said It may never happen again after the recent updates, so, it's not much of a subject for discussion.