What the particular npub.pro page looks like is indeed determined by the owner, and yes it would require an implementation on the npub.pro side; a minimal viable render should be fairly easy to write and then you can request nostr:nprofile1qqsrx4k7vxeev3unrn5ty9qt9w4cxlsgzrqw752mh6fduqjgqs9chhgppemhxue69uhkummn9ekx7mp0qythwumn8ghj7un9d3shjtnswf5k6ctv9ehx2ap0qy08wumn8ghj7mn0wd68yttsw43zuam9d3kx7unyv4ezumn9wshsfqhde8 to add it is what i am saying :).
Generally implementing a kind in other clients is not your concern, but giving users atleast an option outside of your own client (especially if its the first and therefor only implementation), and in this case a fairly 'universal' one in the form a webpage.
Its not so much about npub.pro specifically, it could be something else as well.
It also is yet another example implementation/render, that developers can have a look at/take inspiration from, especially because its outside of the particular usecase-client context. I.e. 'how would/could i display these exercise things in my not-exercise client'.
