How much slower is it? 

Reason I ask is that boosts drop throughput (when connected to them) by 50% for single/dual band extenders. This happens because they have to use the same chip to go router----extender and then extender--device. And they can’t do both at once. So their base throughput is lower than the routers will be. Its why tri-band mesh systems are so popular. The triband and quad band ones have a dedicated backhaul between router---satellites so they don’t take that speed hit. 

So if you’re speeds are dropping from 400 to 200mbps,you’re still doing pretty good and a booster isn’t going to help a lot. If you’re going from 400 to 50mbps, then they might be beneficial.