yes you can, many do.

yes if you power it up/stake, you can earn more hive power through curation rewards and inflation rewards (up to 12% yearly) if you vote on posts that don't get downvoted. It takes 13 weeks to unstake your hivepower back to hive in batches per week.

Currently you can also just trade hive for HBD and if you keep it in the savings portion of your wallet (takes 3 days to remove from there) you can also earn 20% APR on the HBD in monthly payments. This one isn't as set in stone as HP rewards, though and may change based on the block producers deciding on the APR if any.