According to the carto.com documentation it's possible (at least to some extent) to modify the styles of the map, but what if we have a requirement to use a style from snazzymaps.com?
Is it possible to integrate both services together? Is there an easy way to convert snazzymaps styles to carto.com styles?
snazzymaps looks like a way to make google maps styles so that's for the basemap part. CARTO focuses in the overlay data you put on top of a basemap as thematic mappping.
That said, the standard BUILDER dashboards can't use google maps by default, you can use any XYZ tiles service like mapbox, carto.com basemaps and many others. Find here a guide on using external basemaps.
On the other hand, you can use CARTO JavaScript SDK to develop web mapping applications on top of both Leaflet and Google Maps so if you want to use the later with custom styles that's totally up to you. Here's an example on using CARTO.js with Google Maps from CARTO.com developers center.
Disclaimer: I work at CARTO