Sure, of course it's better with people who have a phenylalanine allergy, lol. That's like saying peanut free candy is better for people with a peanut allergy.

The kidney thing, I'll note that your source says it "may be" better, but it's also worth noting that aspartame has had 50yrs of studies against it, and in huge volumes (largely driven by the sugar lobby in the 80s and 90s). It's the most studied food additive in the history of the FDA and has never been meaningfully linked to any sort of major negative health issues.

The acceptable level of intake for aspartame is 50mg/kg vs 5mg/kg for sucralose, and the list of potential side effects is shorter, with sucralose including "diarrhea" and "muscle aches" in the list.