Indoor versus outdoor doesn't really matter for what the antenna is. It's just metal. However, some may be more susceptible to performance changes than others when in proximity to other objects. Plus materials in the structure are always problematic. This is why outdoor antennas work so much better, generally. Foil-backed vapor barrier wall sheathing can block tremendous amount of signal. I could argue for a range of frequencies a piece of scrap wire sticking up outside is better than any commercial antenna used indoors.
TV antennas are made for TV frequencies. They often do a good job for 700, 800, and even 900 MHz just by the nature of their design. A "bow tie" antenna which is a version of the biconical generally exhibits increasing sensitivity as frequency increases, up to a limit. So it was built for 470 through 700 (the current full U.S. UHF TV band) but works well above that. It performs poorly below 470 typically. Sadly, the manufacturer will typically skimp on materials and size, making the antenna too small, so performance down at 470 is worse than it should be (that's TV channel 14) and better at the top than it needs to be.
The discone is a remarkable antenna. Most do not perform as wide as the manufacturer claims but they do cover a very wide range very well. Although they don't look like it they are vertically polarized. They're best at high altitude and good for scanners because the radiation elevation pattern is shaped such that gain is lower for signals near and *under* it and high at the horizon. That doesn't mean it wont work well nearer the ground.
The difficult part is VHF and lower UHF. One reason is for Hertzian antennas (which most are) as the diameter of the conductor is fatter with respect to the length the bandwidth increases. This is easy to achieve at higher frequencies. A simple length of heavy wire is amazingly wide band above 700MHz.
As mentioned, you'll want to keep whatever it is away from things inside like the computer, TV, battery chargers, etc. Even HDMI cables can and do radiate RF energy. (depending on the exact setup and resolution chosen HDMI can radiate a great deal of RF)
