From my understanding, you need to do more hours on the bike in traditional base to reap the same benefits as slightly less time on the sweet spot plan. If you have 10+ hours a week then the slow and steady approach will allow you to really grow your lower end aerobic base efficiency, which I imagine would be great for an triathlete since you shouldn’t need to handle massive surges in power output during your bike leg.
Sweet spot can create the same base aerobic efficiency in less time by working with a slightly higher percentage of ftp. I’m not sure if there is a different recommendation for triathletes but according to the app the sweet spot base is recommended for most cyclist.