Snap Shot Snipers can be considerably more flexible in usage compared to Squadsight Snipers as they are able to move with the team without being restricted to Pistols. They do not require Sniper 'nests' and are able to make full use of certain Sniper abilities which are otherwise of limited use to their Squadsight counterparts.
Damn Good Ground combined with the grappling hook from Skeleton Suit or Ghost Armor nullifies much of the Aim penalty from Snap Shot and allows the Sniper to support the team while still moving from rooftop to rooftop.
Disabling Shot, which can only be used with the Sniper's main weapon, can be used after moving. This flexibility can potentially be a lifesaver, although a well positioned Squadsight Sniper may be better for this.
Battle Scanner is useful in combination with Snap Shot Sniper as the Sniper tends keep up with the rest of the squad allowing for a well placed scanner to lead the way for an attack group.
Because Snap Shot's aim penalty affects Overwatch even with Opportunist, Snap Shot Snipers usually benefit more from Executioner as they have the flexibility to seek out low health targets that have retreated out of sight.
Low Profile allows Snap Shot Snipers to use plentiful half-cover instead of full, which frees up valuable full cover for other teammates; this is especially useful on rooftops. This ability's impact is less significant on Squadsight Snipers as they are ideally too far away to be shot by anything.
In The Zone can be used after moving to flank an enemy, instead of needing to blow away cover or having an Assault use Flush. Furthermore, Snap Shot allows potential use of In The Zone from two different positions every turn, greatly enhancing their killing potential in Terror Site missions, especially with a good weapon.
All things being said, Squadsight Snipers are still unique in their ability to engage targets without ever being in harm's way, while a Snap Shot Sniper fills a role that can potentially be filled by other classes.
This expansion reduces the Aim penalty for firing after moving to -10. This makes Snap Shot Snipers a bit better in Overwatch as the total penalty is reduced to -30 Aim (or even less if they opt for Opportunist).
Squadsight was nerfed to be unable to deal critical damage without Headshot when firing outside of their own sight range. This potentially makes Snap Shot Snipers more consistent high damage dealers as Sniper Rifles have the highest Critical Chance among main weapons, and a Critical hit with a Sniper Rifle often deals more than double the damage of a normal hit.
Snap Shot Snipers make excellent "Ghost" operatives with Mimetic Skin and Low Profile.