Yes, really. But not for drinking through, although there may be a few scenarios where that might be useful. No, the common drinking straw can be used to make a tiny container for solids, liquids, powders and pastes.
To do this, cut a piece longer than you need. Take a pair of pinch nose pliers or equivalent, and carefully smash down one end, with about 1/8″ of flattened straw sticking out from the pliers jaws. Use a flame source (like a Bic lighter) to melt the exposed straw tip, then quickly move the pliers to the melted area and crimp to seal the end. The other end can be sealed in the same manner for “one use” contents. For times when you need access to just some of the contents, you can fold over the open end, squeeze the sides together into a “U” shape, and slip a 1/2″ piece of the same straw over the folded end to hold the fold closed.
These containers can be used for spices, pills, matches, and even small fishing or other gear. A 2″ piece can have a Vaseline soaked cotton ball shoved into it; just clip off one end and pull out some of the fibers to light it. A 1″ piece can be used for a single use antibiotic ointment packet. Powders and liquids are also possibilities. For these, leave an air pocket so if the container gets “smooshed” the odds of it “exploding” and coating your other get is reduced.
Straws are available in many colors, which can aid in identifying the contents, and if brightly colored, finding it in your pack or if dropped. On the other hand, clear straws let you SEE the contents. In either case, use a fine tipped, permanent, Magic Marker to list the contents, and any expiration information necessary. There are various sizes of straws; use the diameter most appropriate to the contents and the kit they go into.
Heavy duty straws are usually a better choice than flimsy ones, and of course, use plastic, not paper or fiber. Those which have an accordion “flex” may or may not be useful. If the length needed is the length of the flex area or longer, these may be superior due to the larger interior volume. However, it is likely that trying to “seal” the flex part of a straw will be less reliable than straws sealed using the straight part.