Connecting battery cells in series VS using boost converter

I need a dc output of 12V 60AH through 18650 li-ion battery cells to use with a 1000W AC inverter to power a 650 Watts computer ( each cell 3,7 Volts 3500 mAh )

One way would be make 17 packs in parallel ( each pack is 4 cells connected in series 4x3,7v=14,8 volts, 3500 mAh ) so the outcome would be 14,8 volts and 59,5 AH ( from total of 68 cells )

How about using a DC-DC step up converter? ( I know Boost converters are not 100% efficient )

Connecting 68 cells in parallel ( 68 x 3500 mAH = 238 AH and 3,7 Volts ) and using a DC-DC Step up converter to convert 3,7 to 12 volts? What is the downside?

• The tesla cars did not become sensational for nothing. Once false move, and you risk major fires. Ideally, every cell should have its own controller. Cell voltages should range from 3.7 to 4.2V if you want a long life. – Indraneel Aug 16 '18 at 14:46

You can buy a ready-made battery, such as the 60 Ah unit from AA Portable Power or the 100Ah Li through Amazon for ~US$600, or heavier, less environmentally-friendly but cheaper lead-acid batteries for ~US$160.