My music library is only about 20 GB. That's still too much to load my 32 GB iPad down with, but I've never felt the need to have more than a couple of decent playlists (just in case) on my iPad. It is not my primary music listening device. I ended up getting iTunes Match to get rid of the commercials in iTunes Radio.
At first the commercials were not a big deal. They were not louder than the music, and often seemed to be relevant. Then, none night I was using iTunes Radio to listen to some relaxing ambient tracks before going to sleep. While the commercial would have been no big deal normally, the sudden contrast with quiet rain and flute music had me levitating at least a foot out of bed {warning; statement may contain some exaggeration}
Anyway, what I really started out to say, is that if the OP has no computer or doesn't want to use one (and that's the impression I'm getting), they won't be able to take advantage of the Match part of iTunes Match. The imported (non-iTunes) tracks have to be on a computer in iTunes to be matched, and if not matchable to be uploaded to iCloud.
On the other hand, if the OP has no non-iTunes content then the virtues of iTune Match is, as you say, about having a large library that wont fit on the iPad available at all times. As long as your library is small enough to fit on the iPad, or you are willing to download and delete stuff manually, then iTunes in iCloud (all purchased tracks visible and downloadable) should be enough. You might as well wait until your library is big enough to bother paying for iTunes Match, unless the approximately $25 a year is worth some slightly better integration (quicker to play not downloaded tracks).
In sum, iTunes Match's main advantages are space savings on the iPad and integrating your non-iTunes tracks using cloud services. If neither of these apply, then save your money. It's not like a person can't change their minds and buy iTunes Match when it does start making sense.
Or like me, you can pay for it to remove some slight irritations, like commercials in iTunes Radio, if that applies.
