popa:
1- Not grape alchohol. It’s the same ethanol in both (we hope), but wine contains sulfites which make some people sick. </pedantry>
2- When you say that using wine is not a dominant opinion, do you mean that it is not widely practiced today (indisputably true) or that it is not dominant in poskim? If the latter, could you provide a list on both sides? I’m genuinely curious since I use wine and I sometimes think the whiskey before the seuda is “cheating.”