The training load does appear to be very light. But I always cruise the first 6 weeks as my body adjusts back to training (usually have 4 to 6 weeks break at end of season). So it would seem appropriate.

Blend of sessions looks good, so I would be hesitant to try and add anything extra. Rather focus on completing everything and getting into the habit of training 1 to 2 times every day. Although extending the weekend ride and run will not ruin the flow of the program (as long as you don't pull up sore).

You mention often burning out before the season starts. Starting off easy and slowly building will definitely help with this. And the article mentions they will publish another program (presumably with more training load).

In Summary, looks good for the first 6 weeks, but you would want to move onto something more substantial after that.

Thanks for the answer.
They do have another plan. Their idea is To repeat the first plan as if it was a "block", improving the quality of the sessions each time.

The other plan le mode a "6 week build phase" To do just before racing.

Do you recommend something else ?

If I don't follow this plan I ll certainly do 2-3 swims (with master), 3 bike (1 with 20-40min of threshold work, 1 short vo2 and 1 long ride) and 3 run (1 long, 1 tempo and a brick fartlek).
But maybe too much for the off season...

There are so many factors, it is difficult to make recommendations. Your training history, availability to train, past injuries, strengths, weaknesses, goals, etc.

Above mentioned plan does not appear to have recovery weeks. This will be an issue when you start to increase the load. Long rides and run seem quite short, but I assume this is because it is designed as the first 6 weeks.

For myself (1-2 HIMs per year, an OD, several sprints, trail races, etc), I train every morning, some lunchtimes and occasionally after work. My weekend ride ranges from 3 to 5 hours, my long run from 90 minutes to a little over 2 hours, my 2 key swim sessions are 4km each sometimes with 2 other swims of around 2.5km. Anything under 10 hours I consider an easy week, over 12 hours is a solid week, over 15 hours is a big week. Leading into 70.3 Worlds in Nice I was closer to 20 hours per week (in an Australian Winter).

In the off season I don't do brick sessions and typically only swim twice a week (about 3 to 3.5km each). Everyone has different ideas about Bricks. I only run off rides specifically designed as Brick sessions. Each session has a purpose, and I don't want to compromise a session by adding a run (ie. you often hold back if you know you have to run off the bike).