Unfortunately, this is one of the many questions that receives "it depends" as a response.
A conventional loan will allow you to utilize cash for the down payment and possible immediate renovations, leaving the remainder of your cash on the sidelines, ready to be deployed for the down payment on your next property.
With cash, it may set you apart from competition when putting in an all cash offer, allowing the transaction to close quickly. You'll also get a better overall return on the property in the long run and maximize cash flow, but your cash is now tied up in the single investment and can't be used elsewhere. That is, unless you BRRRR or obtain a HELOC.
BRRRR, if executed correctly, obviously allows you to recoup most, if not all the cash in the deal to redeploy, thus being more effective than a conventional loan when trying to scale, as you typical leave 20%-30% of your cash behind. This is easier said than done though as you need to balance the amount of work you put into the property in order to get the desired appraisal. Not only that, but you have to find a lender that will provide a loan on ARV and not 70%-80% of what you have put in or the appraised value.
A HELOC allows you to go the cash route, obtain a HELOC and use the cash again to buy the next property. The drawbacks here are that you may only be provided a line of credit for 70%-80% of the home's value, leaving some money still in the previous deal, and the interest rate on a HELOC may very well be higher than a conventional loan.
So, to address your initial question, you really need to ask yourself what you hope to accomplish. Some people don't like the leverage and would prefer to pay in cash while others want to lever up and scale. I don't believe there is any one right answer, but hopefully you will find a method that best suites you ambitions and risk appetite.