Why would I want this over something like mastodon.social or SDF's Mastodon? $7/month seems very steep for what amounts to the ability to have a custom domain and admin responsibility.
How is SDF funded? How can anyone be certain it will continue to be funded, if it offers a service gratis that costs the provider money to operate? Is that funding source aligned with my beliefs and interests? These are questions you don't have when you just pay for things.
Another example: I use FastMail with a custom domain. Yes, I could just use Gmail, but I don't, for the reasons listed above.
Also support from humans who are paid to support you.
This gives you your own instance, which in addition to using your own domain, means you can can set the rules of the server (what kind of speech is and isn't allowed), you can boot people you don't want. You can control who gets in. you can control what other servers are blocked (i assume that is an option in pleroma too).
As a person who've had their VPS disconnected by OVH over a malicious link posted by a third-party on my service, I am very skeptical.
Additionally other instances could very well block all Togethr instances if they see abuse from customers, the same way they can block an instance if they see abuse from their members.
Blocking any given one is of course.
I suppose it would be good to have Mastodon on my own domain, but I really don't care that much (I have had my website on my own domain for 30+ years).
Yes, this is probably not so likely for mastodon.social or SDF, but still. It's just like getting a free email account at some random place, it could be gone every day.
perhaps there is another end user in mind (like groups/organizations)