Do Not Request a Cash Advance!
A cash advance is not the same thing as a balance transfer! In fact, they are worlds apart. A cash advance is used generally by folks in a bind or those who accidentally cash one of those “convenience” checks that the cards send out. A cash advance typically has high fees and a high interest rate, the two biggest killers of a balance transfer arbitrage deal. A balance transfer, if you pick the right card, generally will have no fee and 0% APY interest - which make it at all a consideration for an arbitrage play.
When you make your request, be explicit in explaining that you want a “balance transfer” and not a “cash advance.” Credit card companies rarely make this mistake, giving you one when you expected the other, but people make mistakes and you don’t want to be the one paying if a CSR keys in a request incorrectly.