Will "loose" tapioca from the Indian grocery store work the same to make tapioca pudding as boxed Minute brand tapioca pudding does?

No, the pearls will continue to be bigger than you’re probably used to, and it will definitely take longer to cook. Also, mixes usually include sugar and other ingredients, which you’ll need to add. I’d suggest looking up a recipe, but you could wing it if you’re feeling adventurous!

BTW, the tapioca will work in the same way as any tapioca—it acts as a thickener.

“Minute” brand tapioca is instant tapioca, which has been partially precooked (like “instant” rice). The pearl tapioca sold in Asian stores is typically soaked in water for a few hours before use. It takes more (about twice as much) of the larger pearls to get the same thickening power as instant tapioca.

Here is a recipe for you

The main concern I immediately think of – Will it taste like the store smells ? Even if it’s packaged in plastic and boxed, it may still absorb the odor of anything in the vicinity. The bag may have been there for some time, considering the size. It’s a pretty neutral flavored product so slight contamination may ruin the whole bargain. Is there a best before date ? Now I have a craving for it, I guess rice pudding will do…...