Is it advisable
Is opinion based and you have to decide.
entire monthly salary into a short term or liquid fund and make withdrawals for EMIs, SIPs, paying bills etc at regular intervals? Can I make multiple withdrawals in a month? Are there any transaction charges?
You can. Liquid funds typically offer returns in the range of 7-8% comparable to Bank FD's for longer duration. There are risks involved, the returns can go negative in short term, there can be freeze on withdrawals.
Generally it takes 2-3 days for the funds to be redeemed, some fund houses have reduced the turnaround. There are limits of Minimum amount that can be withdrawn, varies from scheme to scheme and the max amount you can withdraw. These again are scheme specific.
What I want to understand is how beneficial (and practical?) is it to invest for 10-15 days period every month all throughout the year? Would I be able to earn any significant returns?
This depends on the amount you are investing. Roughly if you say 15 days of a month the funds are in such schemes, we are looking at 6 months interest; around 3.5 to 4% [half of 7-8%] on investments. Savings Bank offer around 3-4; so a similar number will be 1.5 to 2%. So on a Rs 100,000 this works around Rs 1500 to 2000. If this is worth the efforts then yes.