If you're not doing anything more extreme than light trails, which I assume are relatively flat, a lightweight bike isn't doing much for you on the trail.

Lower weight will help you accelerate a tad faster, but it's not earth shattering. If you were racing where seconds make a difference over 50 miles, weight has a factor. For joy riding on light trails...weight is a non issue.

Now if you're going to do steep climbs for extended inclines weight becomes a factor. Or if you are going to carry the bike across streams or stuff like that weight becomes a factor.

But riding long distance on a relatively flat trail? Nope. Non issue.

Spend the extra money to get good tires and a nice drive train instead of low weight.

And of course if you live on a 5th floor walk up or something a light weight bike comes in all kinds of handy no matter what kind of riding you're doing.