It can be, but it's aimed at a different way of working. FreshBooks is popular with freelancers, and its strengths — project time tracking that feeds into invoices, expense tracking with receipt capture, and a client portal where customers can see their invoices — suit consultants, designers and other people who bill hours against a project from a desk.
Most trade work is billed differently: a fixed quote for the job, labour plus materials, sometimes a deposit, then a final invoice when you finish. FreshBooks can produce those invoices, but you'd be paying for project and time features built around hourly work. The plan prices we have on file are also in US dollars ($17–$55 a month at the time of writing), so check what you'd actually pay in pounds.
FreshBooks makes most sense for a tradesperson whose income is largely hourly — maintenance contracts, surveying or consultancy — and who needs detailed time records per client, or customers who expect to log in and see their invoice history.