Lots of good information shared on that very subject on this board. Do a "Search" here on this particular forum (click that option up above) and type in the question in the subject line and you'll see lots of chatter about the subject.
Had a fly angler on board recently with what I thought was a clear floating tip on an 8wt... When none of my popping bugs were working properly (submerging after only one or two strips...) I realized that he was using an intermediate tipped line.... If you're fishing and not wanting to use any surface poppers, gurglers, or spun and clipped mullet flies (anything that's supposed to float...) an intermediate tipped line is great. For our purposes in the backcountry of the Everglades -not so good at all... All of my 7, 8 and 9wts are set up with simple low cost floating lines. Where we are the places that hold fish shred fly lines (I rarely have a floating line that lasts more than a year so spending a bunch of money on the latest lines isn't very attractive at all. (all of our floaters are Rio general purpose saltwater lines...).
All of my heavy rods (10wt on up) are in fact loaded with full intermediate lines since all of them are being used for tarpon or other species where we want the fly to sink...
Incredibly insightful. Seems as tho intermediate would belong more on the bigger sticks. My concerns were validated by your statement on fishing flies that need to stay more near the surface. Thanks for sharing your thoughts!