Yeah, slightly stronger solder joint; but, not near as neat. Then you'd have to bend the soldered wires to slide the shrink tubing over the joint which can crack the solder and usually makes the adjacent unsoldered wire weaker.
Now if you wanted to just wrap it with electrical tape, then yeah...it's probably easier. BUT you won't find any of that stuff under MY dashboard! :biglaugh:
I know...that's a lot of explanation for a little solder joint; but, you're talking to someone that has done this since 1994! I'm a little anal about it.