Motors draw high currents due to the mechancial load inertia and if they jam even higher current.
You don't want the relay burning up on startup or if things get stuck.
Contactors can take this extra abuse and have safety approvals for motor loads.
General purpose relays like
Omron G5LE might be rated 16A 250VAC but these numbers are for resistive loads only- no mention of motor load.
I recommend a high power relay such as
TE Potter & Brumfield T92 which are basically a small contactor for $14. Rated 40A 277VAC resistive and 3HP 240VAC motor/compressor use.
OP's motor is 3/4HP and this is a bit of overkill but reliable.