It seems odd that you can't even preview a small cached subset (10 rows?) of a table in Snowflake. I don't even remember a time I couldn't see a table preview in BigQuery, so surely it's not a technical limitation?
The assumption - and maybe it didn't work - was that folks would just try the data (it is free to try). I do think one great thing about the Snowflake Marketplace is how the trials work -- you get a lot of flexibility. Of course, you need a capacity Snowflake account to do so -- but the product is meant for enterprise users.