Desktop software sees its entire Customer Lifetime Value handed over on day one, and is constantly competing against a free, pirated version of itself that anybody can download if you dare set that CLV value above $50 or so.
Software as a Service keeps paying you money every month regardless of what happens, and generally pays you more each month as new customers sign up. And it is by definition un-pirateable.
The only downside you mention is that you have to run a webserver. But you have to run a server anyway. And if you pick the right tech stack, those things don't tend to go down all that often. You don't need "Five Nines" of availability for most types of business software, anyway. Three Nines is fine. Even Two won't generally lose you any customers.
And, of course, Scaling Problems are a Good Thing in the SaaS world. That means that so many people are giving you money each month to use your thing that they're overloading an entire server. That takes a lot of people, so you can use a tiny fraction of the piles of cash they're throwing you to add another machine to your cage. Let's hope that happens a lot.
So yeah, this is not a question that needs asking anymore. Build your thing on the web.
Good luck!