3m dipole antenna? do you mean antenna for 6m band? or is it electrically shortened (coil at base)?
Tuners work both ways, so you can use for example 80m band on 40m band (20m long) dipole, and also opposite way. (“Random” length antennas aren’t really random length, there are some lengths to avoid) But it’s another extra box, depending on power it can get expensive and heavy, and sometimes you’d be better off leaving it near antenna - which means remote control. If you’re carrying your entire radio station with you it’s probably better to use (wire) antennas that don’t require tuner. If you need to use mechanically simple antennas (to hide them from neighbours for example) then maybe ladder line fed doublet is better for you - but OCFD is similar and tunerless. But it’s one of many options
Personally I think that tuners are a solution, but it’s an inelegant one. In some circumstances tuner can be subjected to high voltages/currents and you might have no idea, there are also losses in tuner. There are other ways to make antenna work
Keep in mind that twin pair/ladder line/window line needs distance from anything else, dielectric but especially metal, because air is dielectric, and also needs to be lightly twisted (one turn per half meter or so) so it won’t flop in wind. These are problems that don’t exist with coax. In some builds it can have different impedance depending on weather (water on surface)
3m dipole antenna? do you mean antenna for 6m band? or is it electrically shortened (coil at base)?
Tuners work both ways, so you can use for example 80m band on 40m band (20m long) dipole, and also opposite way. (“Random” length antennas aren’t really random length, there are some lengths to avoid) But it’s another extra box, depending on power it can get expensive and heavy, and sometimes you’d be better off leaving it near antenna - which means remote control. If you’re carrying your entire radio station with you it’s probably better to use (wire) antennas that don’t require tuner. If you need to use mechanically simple antennas (to hide them from neighbours for example) then maybe ladder line fed doublet is better for you - but OCFD is similar and tunerless. But it’s one of many options
Personally I think that tuners are a solution, but it’s an inelegant one. In some circumstances tuner can be subjected to high voltages/currents and you might have no idea, there are also losses in tuner. There are other ways to make antenna work
Keep in mind that twin pair/ladder line/window line needs distance from anything else, dielectric but especially metal, because air is dielectric, and also needs to be lightly twisted (one turn per half meter or so) so it won’t flop in wind. These are problems that don’t exist with coax. In some builds it can have different impedance depending on weather (water on surface)