Yeah, that doesn't say how much of actual consumer spending goes into the goods that are included in the CPI. Even if the CPI were based 100% on non-digital goods, the percentage of purchases that go towards CPI goods could be falling.
Perhaps, but how much of a difference can that make? It's hard to imagine many people spending $100+ on new SaaS/digital goods because of the pandemic.
Not much? Based on the CPI weights given by the BLS[1] at least 82.238% of the CPI is from non digital goods. This is based on summing up the top level categories which are definitely not digital, ie. Food and beverages, Housing, Apparel, Transportation, Medical care. If you drill down into the remaining categories (Education and communication, Recreation, Other goods and services) and eliminate non-digital goods from there you can probably get that percentage even higher.
[1] https://www.bls.gov/cpi/tables/relative-importance/2020.htm