The simple fact is that your brain, brain stem and a few other organs contain a finite number of cannabinoid receptor cells. Some folks have lots of receptors, others not so many, determined by their genetic make-up. But for everyone it's a finite number. Once those cells receive the THC/CBD you inhale, you're done. You can't get any 'higher'. It's why no one ever ODs on weed, no matter what its advertised THC content. When you're high, your brain gradually 'digests' the THC/CBD you've inhaled, your high begins to wane, and you can 'refill' the receptor sites by inhaling some more THC/CBD. But you can only get so stoned.
With that in mind [no pun intended], it really doesn't matter which part of the plant you smoke, so long as it contains the THC, CBD and other cannabinoids found in various strains. Buds are obviously where the action is, but sugar leaf, fan leaf and even stems have the chemical entities we all enjoy. I got blasted back in the 1960s when I smoked whatever leaf we could get our hands on. It was usually the whole plant, dried and crumbled. There were some buds, or parts of buds; but it was mainly leaf, because the whole plant is predominantly leaf.
This is a little simplified, because there are a number of different cannabinoids besides just THC and CBD, and they lock onto different receptor sites. CBD, for example, goes primarily to the brain stem, where it can make us bleary-eyed and quite 'relaxed'. THC tickles brain sites responsible for sensory input [sights, sounds and taste], mood elevation and memory [formation and retrieval]. But the point is: You don't have more receptor cells just because you have more, or better, dope. All you have to work with are the cells God gave you [or Mom and Dad, if you prefer].
I'm like everyone else nowadays. I love buds. They smoke milder, they taste better and they pack way more punch, so you don't have to inhale as much. But leaves will make you giggle, make your food taste better, and make you bleary-eyed, just like bud. It's a Beer vs Champagne comparison -- not club soda vs Champagne.