Accounting demand has two completely different shapes stacked on top of each other. The January through April wave is high volume, price sensitive, and largely people who could have used consumer software. The fall extension window is quieter and stickier. In between sits the search behaviour that actually builds a practice: an owner typing an entity or a situation into Google, not a service. "S-corp election accountant", "cash to accrual conversion", "CPA for construction contractors", "accountant for a business sale". Those queries carry a problem statement, and a firm that has written a real page about that problem is in a very different conversation than one ranking for "tax preparation".
The competitive set is unusual because it is not only other firms. Consumer filing software, storefront chains, and directory sites all sit on the generic terms, and they will always out-spend a local practice on volume queries. Where they cannot compete is specificity. Nobody at a national brand has written about the depreciation question a dental practice faces when it buys a scanner, or how a restaurant group should handle tip reporting across locations. Specialisation is both the marketing angle and the pricing angle, and the site has to state it plainly rather than listing every service the firm has ever performed.
One more thing shapes this vertical: capacity. Most partners do not want more leads, they want fewer and better ones, and they want them before March. A campaign here should be judged on whether the enquiries arriving match the work the firm wants to sell, which means the copy has to disqualify as deliberately as it attracts. Publishing who the firm is not for, and what an engagement actually involves, filters harder than any form field.