Is there any advantage to trading a bull butterfly spread over a bull call spread? Is it cheaper to trade? For instance, I'm looking at the 235/245/255 Nov 19 bullish butterfly for NVDA. Its max cost is $195 and its max return is $805. Yet a Nov 19 expiring 235/245 bull call spread for NVDA has a max return of $635 and a max risk of $365. Would you choose a bullish butterfly over a bull call spread?
Much depends on your view on Market Direction / Vols ... also have a look at 235-240 Call vertical ... usually similar price to Wider Butterfly
If you are looking that many days ahead I think it's best to widen the fly. I like flies over spreads when theta is in play usually under 30 DTE. I mostly trade them under 5 DTE.
The fly may be more attractive if the vol skew is favorable. If not, you usually want the spread with smaller number of legs, to limit transaction costs.
a fly is not a IV vs RV play and it doesn't make any sense to use it to profil from decay. a fly is a pure vol play, either against skew or overall vol in the particular term bucket. A bullish fly will profit when you place the short strike above market and the stock goes up while vol decreases or short strike vols decrease as they are sliding down the skew. Decreasing vol means you get additional deltas via vanna.