It depends on where your clients live and what kind of warranties you can offer on them.
If the location isn’t prone to high-wind storms during the year (tornadoes, hurricanes, etc.), then it’s probably not worth it. These windows are meant to keep the entire home intact during high-pressure weather situations - they aren’t necessarily built to not break.
If your client is looking for security from break-ins, not weather damage, impact is not their answer. Impact glass is typically not tested for blunt force like a crowbar, so make sure they understand that and if they want security, offer other options.
Also make sure that the warranty offered on the windows is reasonable. Just because it’s impact doesn’t mean it can’t break, and replacing an impact window could get very pricey, as the client will realize when they see the estimate.
Hope that helps!