chore: make download only the default on _impl

Author: luabida

README.md

@@ -52,28 +52,39 @@ docker compose -f docker/docker-compose.yaml down
 
 ### Simplified Database Functions (New in 2.0)
 
-The easiest way to get data as a pandas DataFrame:
+By default, the high-level convenience functions query and download data locally, returning a list of paths to the downloaded Parquet files. This allows you to inspect the file structure or load them with your preferred tool (e.g., pandas, Polars, DuckDB).
 
 ```python
 from pysus import sinan, sinasc, sim, sih, sia, pni, ibge, cnes, ciha
 
-# Download SINAN Dengue data for 2000
-df = sinan(disease="deng", year=2000)
+# Download SINAN Dengue data for 2000 and return a list of Parquet paths
+parquet_files = sinan(disease="deng", year=2000)
 
 # Multiple years
-df = sinan(disease="deng", year=[2023, 2024])
+parquet_files = sinan(disease="deng", year=[2023, 2024])
 
 # SINASC births for São Paulo, 2020-2023
-df = sinasc(state="SP", year=[2020, 2021, 2022, 2023])
+parquet_files = sinasc(state="SP", year=[2020, 2021, 2022, 2023])
 
 # SIM mortality data
-df = sim(state="SP", year=2024)
+parquet_files = sim(state="SP", year=2024)
 
 # SIH hospitalizations with month
-df = sih(state="SP", year=2024, month=[1, 2, 3])
+parquet_files = sih(state="SP", year=2024, month=[1, 2, 3])
 
 # CNES health facilities
-df = cnes(state="SP", year=2024, month=1)
+parquet_files = cnes(state="SP", year=2024, month=1)
+```
+
+### Loading as a DataFrame Directly
+If you prefer to load and combine the data automatically into a single pandas DataFrame, pass the as_dataframe=True parameter to any of the functions:
+
+```python
+import pandas as pd
+from pysus import sinan
+
+# Download and return a concatenated pandas DataFrame
+df = sinan(disease="deng", year=2024, as_dataframe=True)
 ```
 
 ### Listing the files