So snails will get the glass better but you run the risk of them damaging plants? Am I understanding the comparison correctly? Also is it easier to keep smaller shrimps with a betta alive if say you have a good amount of dwarf tears and java moss growing?
For the most part, yes. "Run the risk" may be a slight understatement; I've always had snails devour plants. There are snails that supposedly won't eat plants - Malaysian trumpet snails. They didn't work for me and were super expensive, but they're probably your safest bet from what I've read. Shrimp on the other hand, are almost all 100% plant-safe and even the ones who don't technically eat algae will contribute to their wellbeing by scavenging for debris among their leaves. In some cases, your standard ghost and cherry shrimp will even eat algae. I've had a few out of many shrimp that have continually donned a dark green belly - and I sure as heck wasn't feeding wafers!
The plants will make it infinitely easier if a "good amount" equals enough for a good sized hiding place. With the moss around, you may never see the shrimp though! I had a huge clump of guppy grass in one of my tanks and recently figured out a shrimp I literally hadn't seen in a month, was living inside the mass of it. As long as your plants are sizeable enough to provide cover, I'd say go for it.
If you're wondering about your bettas tolerance to the shrimp and are concerned about shelling out big bucks for the ornamentals, try starting with ghost shrimp. They're feeder stock, and the LFS I work at sells them 6 for a dollar. I belive that price is pretty standard as is the availibility in different stores. Throw them in, see how it goes. Worst comes to worst, your betta got a high quality meal and you lost a buck. Sure beats losing 20.