What is cost effective doesn't matter if you want to play, and gain experience, with fiber. Do whatever you want.
I know a farmer with 40Gbps fiber in his barn, because he wanted to play. If you can afford to play, there are worse ways to "waste" your money. He translated play into business over the years. Apparently, you have to do something while the fields are snowed under. :-)
Conduit is always a good thing when you have access to put it in. Of course, conduit is expensive too. But it sure is nice when you decide you should have run more cables to a particular location. :-) If the walls are open, run fiber and cat6. Knock yourself out. You may decide to route speakers, intercom, USB, or HDMI across the copper for some reason. With conduit, you can change what's in the wall if you want large gauge speaker cables, or whatever.
In my home, a couple decades ago, I ran four strands of Cat5 to every outlet. Overkill, I hoped. Later on, I sometimes wanted more at various outlets when I got to playing. Re-arranging the house some years down the line can lead to you wanting connections where you never thought you might. That's where those plastic tubes beside every power outlet come in handy, but only if you put them in when the walls are open. I didn't have conduit. I did have four reels of Cat5 and it was as easy to pull four as one.
Whether it's worth it, or not, is up to the guy, or gal, putting it in.