Any benefits in just training the FSP?

As in, pick 4 FSP (L-sit, planche, front lever, back lever) and skill work such as handstand and train only these on workout days. Would there be any benefit to this, as opposed to FSP and FBE work afterwards? I know Coach Sommer has stated in the book that one can get quite strong training just the FSP, but I'd like to hear other opinions too, please

It would very likely limit your muscle gains and strengthen your tendons, and both are good if you're trying to get a very high strength/weight ratio.