Behind the Ear aids do tend to last longer due to the shape of your ear canal changing with time. A CIC would require a completely new aid if the ear changes shape where-as this doesn’t affect a BTE.
CICs also are more prone to breaking - as they are at risk of damage from sweat/wax, which requires them to be sent off if fixed.
There are several different types of BTE’s, there are ones with thin tubes, ones with moulds and there are also RICs (receiver in the canals). Looking at your hearing loss, it appears to be in the range for RICs. Rather than sound travelling through a tube to your ear where it is at risk of degrading, the sound is produced directly in your ear. Because the distance between the receiver and the microphone is longer than if it was produced behind your ear, the risk of whistling is much less. Also, if your hearing loss deteriorates at all, a more powerful receiver can be fitted by your audiologist at no extra cost so they should last longer. Definitely worth checking out the STarkey Zons, Resound Dots or Phonak Audeo Smarts.
I don’t mean to sound like I am criticizing CICs, they have their place - but if it is longevity and sound quality you are after then a BTE may be more appropriate.