Keeping a boiler hot to provide hot water via a coil 24/7 is expensive. Depending on your utility costs and availability, as said, an indirect may be a good choice, or maybe an electric WH, or possibly a gas one, but that's unlikely if you're using oil.
In most of NY an indirect water heater coupled with a heat purging boiler controller will be cheaper to operate than an electric water heater.
See system #3 in Table 2 in this document.
With heat purge control heating hot water only, no space heating load will run about 10% below the steady state efficiency of the boiler. So after standby & distribution losses an 80-85% efficiency pretty-good older beast will run at 70% during the summer. This week
the NY state average price of oil is $3.27/gallon. NY
residential retail electricity is averaging 19.3 cents/kwh.
A gallon of oil has 138,000 BTU, and at 70% would be delivering 99,600 BTU/gallon into the indirect. Normalizing to $/MMBTU (million BTU) that would be 1o.35 gallons/MMBTU, which at $3.27/gallon costs $33.84.
A kwh of electricity is worth 3412 BTU. Normalizing to MMBTU that would be 293 kwh/MMBTU, which at $0.193/kwh costs $56.55/MMBTU.
Without heat purge controls summertime water heating with an indirect on an oil boiler could run as low as 38% (system #2 in the Brookhaven document), at which point the operating cost is comparable to that of an electric tank with 19-20 cent electricity.
During the heating season heating water with the indirect is at an efficiency comparable to the steady state efficiency of the boiler, since the standby losses are lower, and shared between the heating load and domestic hot water load. So even without heat purge control the annual cost of heating hot water will be cheaper with oil than with electricity.
With a heat pump/hybrid electric water heater it gets more interesting, since the water heater if placed in a basement boiler room converts summertime basement humidity into heat in the tank using 1/3-1/2 the kwh of a standard water heater, and during the winter it converts the standby losses of the boiler in the boiler room into heat inside the tank. The down side to heat pump water heaters is the slow recovery and higher up front cost, but it may be worth considering if you normally run a dehumidifier in the basement to keep the humidity low.