If you're not fighting easy trash you'll have plenty of time to find a perch and start sending death downrange.
If you're fighting trash, toss a grenade and follow with Suppressive Fire and Rifle Shot, no need to deploy cover at all. If you're desperate for cover abilities, wait until you get your insta-Snipe after deploying cover, and learn to cover dance with portable cover.
Half the challenge of being a Sniper is knowing when to look for cover, and when to stay mobile.