"I understand that this amount doesn't need to be reported or included if no distribution occurred."

If you have a 1099-R, then by definition a distribution occurred. The 8606 has the parts or sections, because different activities need different consideration. Roth or Traditional, inherited from spouse or non-spouse, and basis or not. That's why the FMV is included in some of the Parts on that form.

"Is there any tax consequence (positive or negative) that may occur in the future by entering or failing to enter this information?"

Yes. There is dependent info that would make this important for specific activities, such as Basis in a Traditional IRA or an inherited account, or in a Roth when Roth distributions are taken early, or Conversions.

"I entered this information and it doesn't impact 2020 tax return"

Because of the 1099-R, or simply because you got handed a 5498? You use the 5498 to confirm what the taxpayer tells you they did with the money that is on the 1099-R. You enter the 1099-R, because it is reportable. FMV and Basis are needed, well, when they apply and are needed as part of the computations.

"When the client does take a distribution in the future, could it be beneficial to have this ongoing cost basis in Lacerte?"

Yes.

Let's review.

1099-R is for money Out. A rollover, a change from one type of account or plan to another (a 401(k) or SIMPLE IRA is rolled into a Trad IRA account when the employee leaves or is terminated, for instance).

A 5498 is for money In. Example: When the person with a 401(k) having both pre- and post-tax money in the employer plan, rolls the post-tax part into a Roth and the pre-tax part into a Trad IRA. Or, when the post-tax part was not split off and got put into a Trad IRA, where it becomes basis.

And sometimes you might need to file form 8606 without a tax return:

https://www.irs.gov/instructions/i8606