This really makes a difference!  Some timing statistics (on
test/test2.html, a document with no TAL contents):

talizetree    :  2.190 secs for 10 calls, i.e.  219 msecs per call
printtree     :  2.870 secs for 10 calls, i.e.  287 msecs per call
compiletree   :  0.250 secs for 10 calls, i.e.   25 msecs per call
interpretit   :  0.110 secs for 10 calls, i.e.   11 msecs per call

There are two ways to go from a DOM tree to text (the assumption is
that the DOM tree is already in memory):

talize + print    : total 506 msec
compile+interpret : total  36 msec, or about 14x faster

If we cache the compiled program, we're down to 12 msec, or over 40x
faster.

So compilation + interpretation are well worth it!  (I.o.w., creating
a DOM tree is very slow.)