I'd be inclined not to use or pay for a feature like this, and here is the reasoning why:
- PostgreSQL is a mature and thoroughly-tested database system, and it supports features that make implementing the business logic you mention relatively straightforward
- E-mail is a mature and well-tested standard, and the systems that can send and deliver it are well-known although they can sometimes require careful configuration
The logic required to implement a link between the two is small (in terms of lines of code), and it shouldn't introduce much internal overhead to review and deploy. Explaning and documenting it for a wide audience should also be feasible.
To introduce a third-party component (and perhaps an entire low-code platform to support that component?) would require at least the same amount of review, while also being updated, modified, and discontinued at the whim of an external vendor. That doesn't seem to be a good trade-off.
That's not to say it's not a potentially viable business idea. It'd be possible to persuade people that they could and should pay for a feature like this. I just don't personally think it's sensible for long-term business integrity.