I don't question the "purity of artistic passion" EVER. People need a roof over their heads, running water and electricity, clothes on their backs and food to eat - if they ask people to voluntarily donate some money for that, they're not compromising their vision, they're not somehow less pure and perfect artists, and their creations are not inherently less valuable.
The myth of the starving artist is a damaging one. Artists handing their work out for free are not morally superior to those who ask money for doing so. Artists asking for some money are not sellouts or greedy; they're just trying to make ends meet. And "passion" isn't something that should be measured in whether or not they're asking for money; it's really freaking hard to stay passionate about something when you're starving and can't pay your bills.
(note: @keii4ii - I realise you aren't blaming the artists for asking for money; I'm just quoting this part of your post because it captures an attitude that I find far too common)
I run a Patreon to support my creation of comics and other art, and my backers get to be two pages ahead of regular readers, and get a weekly sketchpost/sneak-peek update of behind-the-scenes material for my webcomic and other projects. Higher-tier backers get access to all of that, as well as hi-res PDFs of my comics whenever chapters wrap up, or whenever I finish a side-project. I've been thinking of adding Patreon-exclusive wallpapers, but I haven't decided yet.
I don't hide big chunks of my comic behind a paywall, I don't hold pages "hostage" until I've reached a set amount of donations - and I will continue to post my comic for free. It's just that people who do throw a little money my way (emphasis on "little"; access to all my Patreon-posts costs less than a cup of fancy coffee a month) get a few extra perks.
It should also be noted that I am an illustrator/comic artist. This is what I do for a living. However, freelancing in the artworld is an uncertain kind of life, and running a Patreon gives me a small but dependable trickle of monies with which I can pay for necessary stuff. So far, my income from it is paying for the webhosting on my main site, and the occasional new pencil, and maybe a few cups of tea. I'm hoping, in the future, it might help me pay for a premium membership on Picarto, so that I can offer Patreon-exclusive livestreams.
I've been considering Tapastic's support-program, once I reach the required number of subscribers, but I'm also thinking of maybe just sticking to Patreon. That way, people who want to pitch in can do so, without supporter-exclusive stuff on Tapastic annoying those who don't.