I’m a mechanical engineer, and have an extensive background in engine lubrication system design for a major auto manufacturer (not Honda). I strongly recommend that you use the grade of oil recommended by the manufacturer. You may not be at risk of engine damage by using 5W-30… but then again it’s possible that you are.
For example:
5W-30 will be thinner than 5W-20 as oil temperature drops below 0C, which could result in insufficient bearing film thickness on cold starts.
On the other hand, 5W-30 will be progressively thicker than 5W-20 as operating temperatures increase. The performance of hydraulic systems (such as the variable valve timing system used on your vehicle) is affected by fluid viscosity. It’s possible that the engineers specifically chose 5W-20 because the thinner operating viscosity enables faster response of the spool valve and locking pins. If using 5W-30 results in the risk of the pins not being able to engage fast enough, then you’re at risk of valvetrain damage.
I have no knowledge that either of these examples is actually the case on your particular engine, but these certainly ARE the kinds of design and development details that go into the selection of oil grade. There are many such issues, and the system interactions are very complex. Do yourself a favor: don’t second-guess the engineers.