It’s a little hard to say without taking into account a specific recipe. In general any substitution needs to have differences in fat, structural elements (starches, fiber and protein) and sugar (if any) taken into account and adjusted for. For instance, if you decide to use pistachios in lieu of almonds, you may need to adjust the fat content of the recipe to account for any difference in oil content between the two nuts.
But you may not need to do that- in some recipes the nuts are treated as an add-in, not part of the structure of the cake, and so small differences aren’t so important. Kind of like with chocolate- if you’re adding chips to a recipe, you can pretty much use whatever you like, as long as it has the same weight and chip size, the only issue to consider is taste. But with chocolate that will be melted into a batter, the fat and sugar content become more important and substitutions may require adjustments elsewhere in the ingredients to compensate for differences.
From a flavor standpoint, again, it’s hard to say without taking a specific recipe into account. For instance, there are some recipes that use untoasted ground almonds for texture, and so a mildly flavored substitute would be desirable. In other recipes, the nuts may be toasted and be a featured flavor, in which case another flavorful nut- perhaps pistachios- would be appropriate. You may have to take it on a case-by-case basis.
I’ve never tried bennecake flour, but it sounds interesting, thanks for inspiring me to go look it up. For some reason I want to go make pancakes out of it!