Yeah, HuC's text-output functions (e.g. put_number, put_string, etc.) just update the background/tiles table with your font's tiles.
Don't forget that you can change a sprite's priority to make it appear underneath the background (and thus the HuC-libraries-outputted text), but you'll only be able to see through the color-0 part of your tiles... so, not really useful in most applications, but it can come in handy and is worth remembering. (Use spr_pri(0), if I recall correctly, to have a sprite appear underneath the background)
For truly sprite-based text, I suppose it's simple enough to just reload some font data into your sprite ram area and set up a few sprites--or something similar. I guess this mostly comes up on titles, credits, stuff like that, as well as your on-screen display for score/etc. Since this sprite text can usually be kept to a minimum, it's generally easy enough to manage with your own code. I don't think the overhead from a flexible sprite-based text output library would really be worthwhile on PCE... maybe for subtitling cut-scenes in games or something, heh.