Dynamic typing also lends it's self to portability at cost of translating between representation formats.
Xml/json/html are examples, where data is represented in portable string format with additional data (metadata) to indicate what type the string data represents when translated into native hardware format.
Comma delimited file can be manipulated like a database via unix commmand line tools / awk. For small files, not an issue. For larger data sets, fixed-data types offered by databases provide for processing/storage efficiencies.
Spreadsheets, kinda stradle the processing middle ground, where don't really care about data type until want to do something with the spreadsheet cell(s).