I believe most residential internet services block outgoing connections on port 25, so you would either need to upgrade to a business plan or pay for a cloud server to run your own email server.
If you just want to receive emails then it's probably fine.
On top of that, FastMail has a killer feature if you like have different addresses for different things. For example, say your email is name@example.com and somewebsite.com is asking you to provide an email address.
You can just put in somewebsite@name.example.com and FastMail will automatically route that to your mail email as if you had used name+somewebsite@example.com. You don't need to do anything beforehand and can just create these emails on the fly when you encounter a sign-up form.
It simplifies things greatly and if you start getting spam on one, you can just block it.
This is one of my favourite FastMail features.