Probably not worth it if you have to buy the points, no, even if the points get cheaper the larger amount you buy.
Possibly worth saving up points for the longer delegations? I stopped using ecency some time ago, so I have no idea how many points it's feasible to earn per day.

7 days for 1500 points ≈ 214.3p/day
30 days for 6000 points = 200p/day
90 days for 17000 points ≈ 188.9p/day