Just had our plumber round to service ours so I asked him what he thought.
His answer – if it is a new boiler under warranty then definitely yes (ours is for reference). If anything went wrong and the warranty had been voided by not having it done it would likely cost more than the sum total of the services to fix.
If it is an older boiler – up to you. It can help prevent stuff going wrong however usually if something fails, it fails; serviced or not. The only other thing it buys you is peace of mind re: things like carbon monoxide emissions.
Seemed an honest enough answer and that’s from someone who makes money servicing boilers 🙂