Well top speeds are equal for obvious reasons. In theory the higher torque will bring you to speed faster on inclines. The CX has a higher motor assistance %, which means you don't have to have to pedal as hard to achieve the same speed. The Active Line is aimed at city riding, light trails and the CX Performance at eMTBs/cyclocross. Of course, bike manufacturers are not fixed to those applications. You'll find CX motors on heavy duty commuters and tourers.
I don't have the best historical perspective because most of my own research was comparing the 2019 to 2020 models, so take what follows with a pinch of salt. But through my reading I did establish that the older Active Line models will suit city riding better than that generation of CX Performance because after the 15.5mph cut-off, resistance to muscle powered pedalling after the cut off is massively reduced for the Active Line, unlike the old CX line which will feel more sluggish. This doesn't matter much for the CX range aimed at eMTB bikes, because you really wanted the extra torque for climbing. It was the major trade off, but the extra torque is particularly useful for the stop start riding your might do on an MTB.
Bosch just updated their CX line this model year (2020), the new version is nearly half the size of the 2019 version and brings it in line with the Active Line Range, which will mean weight savings and more compact designs, but most significantly it does away with the aforementioned resistance after the motor cuts out, it is supposed to feel more natural, like a real bottom bracket. So the lines between the models are now more blurred than they were. Whether you need the extra torque and to answer your question about whether it's worth it for you, we will need to know how you intend to use the bicycle you ultimately buy and where you ride it. A heavier rider, or those carrying luggage would benefit from the extra torque.
If you are prepared to wait to get your hands on a 2020 CX Performance bike, you can have the best of both worlds. The CX line also gets
the new improved eMTB mode, which changes motor assistance dynamically between 110-320% depending on how hard you are pedalling, something the Active Line is missing.
