Of course you can, but do you actually derive a benefit from doing so?
What you gain is that the GPU is doing the not-quite-trivial work of sampling texels, antialiasing, blending pixels together, and all that. Sure, you can do all that on the CPU no problem, but why do that when there's a dedicated workhorse for the task?
You still have to perform all the unicode normalisation, layout, kerning and ligatures on the CPU, and (at least for small font sizes) the amount of data you upload to the GPU is very similar for both the vertex buffer and texture cases.
Yes and no. Kerning and ligatures (or formatting a paragraph) you certainly have to do yourself. Unicode normalisation is not something you do at all. This abomination (which in my opinion is a good reason why Unicode is totally unsuitable for what it's used for) is something you should handle by policy or in the build pipeline. Your renderer should not have to guess how to compose a glyph, and your text system should not have to guess how to compare or sort two strings. There should be one and only one possible way, even if Unicode allows for 2 or 3 ways that are equally "valid".
The amount of data you send to the GPU can be as little as a point and a character index, so anywhere from 6 to 12 bytes. Quad extents can be read from constant buffers at no performance penalty on present-day GPUs. Compared to that, a "small" character may easily have 200-300 pixels, which is over 10-15 times as much for an 8-bit monochrome bitmap (or 30-45 times for RGB). Color and size don't change every 3-4 characters (not normally, at least!), so it's reasonable to just set these as uniforms.
Ah yes, but Mandarin is something you would not normally consider anyway, unless some stupefied executive forces you to.
Mandarin means Chinese market, and while every executive nowadays seems to think of China as El Dorado, reality has it that it means a lot of work and many extra complications for very little revenue. The Chinese pay a lot less money for the same product, if they do.
So unless you're working for a company like Microsoft, Blizzard, or EA (who will want to be in this market despite bad revenues), it's a good business plan to grab every guy pronouncing "Chin..." and arrange an accident involving him falling out of the 8th floor window before he can finish the sentence.
Note that this isn't about not liking the Chinese, it's about being reasonable on what you have to invest, what risks you have to cope with, and what you get back.
Take Blizzard and WoW as an example: If you research on the internet, you'll find out that WoW costs around 7 cents per hour in China. Compared to Europe where the same game costs €12.99 per month (~16.91 USD). At an average weekly play time of 20 hours, this translates to slightly over 21 cents per hour. In other words, Blizzard puts extra work into localizing and setting up extra servers, and takes up the risk of doing business in a location where laws are... somewhat special (a very friendly wording), only to sell their product at 1/3 the rate.
Maybe that makes sense from an executive point of view if you assume that you get another 1 billion subscriptions (but, do you, really?), and those outweight the fact that you're selling under price. For every "normal" business it's just madness to think about such a plan.