Yes, but also not as much as people make it look like. When you pay through Steam you also get a dynamic discount, although it's smaller than the one you get on vRP. It starts at a purchase worth of 500 vRP or more; is about 3% at 1200 vRP; 6% at 2400 vRP; maximum is 18% on a purchase worth of 5000 vRP or more.
That´s a good point not many people might know, so it´s worth combining several purchases in the same operation if using steam wallet funds. The dynamic discount does not apply to VRP so if you pay partially with old VRP then that gets deducted first and the discount is on the pending amount. Also worth rememberin that BF is less than 2 weeks away and that the Steam sale starts on the previous Wednesday/Thursday depending on time zones. RRE will likely have some sort of sale on too, although in the summer they didn´t coincide.