Yes pls give the route some time to build up. The airport has been going full belt on pushing this on its social media channels and hopefully todays launch ceremony will be another reason to get some airtime for it.
The fact that this route is seasonal must mean Loganair is going after outbound holidays from Bournemouth. In the past Bournemouth did really well with its channel islands routes in conjunction with Southampton and at one point had 7 return flights on a single Saturday each summer, so one single flight should be fine.
By the way Bournemouth is home to one of the largest financial services centres on the South Coast (JP Morgan, Liverpool Victoria, Barclays and many others are based there). One would think this would be cause enough for the route to be a strong performer.