The gin is there because it imparts the juniper flavor that works so well with venison. A lot of venison recipes have juniper berries so I suspect this is just an easier way to give that flavor without having to fish the berries out.

I might do this with beef, but not a tenderloin... I also think I'd cut the gin back a bit for beef, as I think it would be a little overpowering with the milder meat. A tenderloin in particular has such a mild flavor compared to venison... maybe a beef rib roast? I dunno, but I don't think a beef tenderloin would produce the best balance of flavors here- wouldn't do justice to the meat or the recipe.