To varnish or not to varnish?

Until recently, I was totally against varnishing my paintings. I thought, "why ruin a perfectly good painting by making it look all shiny and hard?" 

However, after reading a bunch of online articles like this and this and this about the benefits of varnishing, and speaking with a couple of gallery owners who said "absolutely you should be varnishing your acrylic paintings," I changed my mind. 

Benefits of varnishing: 
-protection against fading
-protection from dirt and dust
-protection from moisture
-dried acrylic paint is softer than dried oil paint and therefore more prone to being damaged - varnish is much harder than the paint and acts as a physical protectant from dents 
-can make acrylics shinier like oils (if you're into that)
-can bring out colors, especially darks (if you use a gloss finish)
-can be removed and reapplied if looks yellowed or dirty after many years 

Downsides:
-turns acrylics extremely shiny (if you use gloss finish)
-can make darks look cloudy (if you go with a matte finish)
-can eventually yellow 
-smooths out uneven textures (for me, this is a downside - I love the subtle textures that I capture in my brushstrokes)
-unsure what the results will be in 100 years (water-based acrylics similar to those available today weren't even created until the 1960s!)

But seeing as how it's virtually impossible to clean or restore a painting that hasn't been varnished, I figured I should give it a try.

isolation coat supplies - dedicated brush and container

I won't attempt to give a tutorial as I'm no expert, but I followed the process laid out here and first gave my paintings an isolation coat. (While acrylics are still considered "young" as a medium, the idea is that an isolation coat will protect the paint from removal or damage in the instance that the varnish is removed or replaced.)
 

varnish supplies - all marked with matching washi tape to differentiate from others

Once completely dry, I applied two coats of gloss varnish, following this description - 3 hours in between coats, allowed final coat to dry overnight. 
Varnish requires its own dedicated brush and container. Any residual paint coming off a brush or dish can ruin a painting's surface. (and yes, I did buy two of the same brush. 2" wide soft bristle with tapered edges.) I decided to go with gloss varnish as it was important to me not to lose the depth of my darks. I used a brush application varnish instead of a spray mostly because it's still below freezing outside and sprays can't be used in environments below 50*F.

 Results:
-much shinier, which is fine
-smoother texture - it bothers me a little that I lose some of the original brushstroke
-blacks look richer, especially in person
-definite harder surface, which feels more permanent and safer - like I don't have to worry about it as much

 I am still trying to accept the loss of that subtle brushstroke texture. I am guessing the texture would be more prominent without the use of the isolation coat, but in the event that I would need to remove or replace the varnish on one of my paintings, I am glad to have it there as insurance. This could also possibly be remedied by the use of a spray varnish, which would go on even thinner than a brushed varnish, but I won't be able to test that until the weather warms up.

Given that a lot of my paintings incorporate vintage fabrics and graphite on the surface, I appreciate the added protection that the varnish gives - nothing is worse than your artwork being smudged or damaged after it's finished. 

What are your thoughts on varnishing? Do you have a preference for gloss vs. matte or spray vs. brush? Any tips or tricks?