Notion plateform question

Hello

It's now several months that I have noticed many saas building products with the basis of notion/airtable.

But I don't get the point, regarding the users. Why the user will use notion and pay for an addon of notion ( for ex, website building, forms , helpdesk...), when he can directly pay for a saas that is providing the same value.

I feel like this notion/airtable are only annoying.

I don't understand the added value of notion/airtable. Some can explain please ?