Light Glare
What about light glare? This depends greatly on the privacy filter being used. Many film options provide at least some protection against glare with an overall screen darkening (on the downside, you may have to increase your brightness beyond where you used to have it). Some of these screens are specifically designed to cut down on glare and make your screen easier to see. Others may include features to cut down on blue light so that your screen doesn’t affect your sleep pattern at night time.
There are a lot of options here, but there’s no sign that Apple will include any specific light glare features with its privacy screen. Also, Apple platforms have a built-in benefit to turn on Night Shift and cut down on blue light anyway, so it’s unlikely the privacy layer is designed to do this, too.