people don't want yet another monthly subscription so that's going to be a harder sell. even though the business advice is that monthly subscriptions are better for you, the business owner, you can't forget about your customer. who wants to setup a subscription for something they think they're only going to use once or twice? and then have to go through the bullshit of cancelling.
True, in cases like OP a one-off purchase will be better. But I also have business customers with regular and ongoing document processing needs for whom a subscription does work.
I expect the answer may be a combination of the two.
