With the right type of screw (a masonry screw) then you can fix without a plug. But not all screws are masonry screws, and not all wall materials are suitable for masonry screws. I'll bet that many of those videos don't make a clear distinction.
This kind of stuff - putting up shelves and brackets - used to be common knowledge. But I guess with the internet/app age anything requiring physical labour and common sense is something of a challenge now
Yes. The safe option is to use plugs. Simple.
Presuming that you found the wall to be solid...... Drill a couple of test holes. If the dust is red then you're drilling in to brick usually. If one hole is red and one is grey then you have brick but one hole hit the mortar between the bricks. If it is grey then you are drilling in to breeze block. If it seems like it's raining in doors then well done, you have found a concealed water pipe (see note 1). If there's a flash and all the lights and power went off and you're left wondering what that funny smell of burning is then you were lucky; you hit a mains cable in the wall but survived (see note2). If you wake up in an ambulance or in hospital then you were still pretty lucky but you'll have some scars to remember the incident by (note 2 again). If there's a big bang and you wake up strumming a harp then congratulations on finding a gas pipe or electrocuting yourself to death. (Don't bother reading any note 3, it's too late for that)
Both types of wall need plugs. Brick will be fine with your basic brown rawl plugs and 2" screws. I hung a bracket for a customer a couple of weeks ago on a brick outer wall with 5 screws as above. To test the strength I hung off the wall plate. I weight 15½ stone (98kg), so a 15kg telly will be perfectly secure as long as the plugs and screws are anchored securely.
Breeze block is not as solid as brick. You don't even need a drill. You can make holes in it with a screwdriver!! Fixing-wise you can go with Fischer SXR 08 TV Fixings which are a bigger longer plug and screw arrangement, or my favourite is chemical/resin anchors & studs.
Notes
- Turn off the water supply at the stopcock and call a plumber and your insurers. Total cost approx £150. Use a pipe & mains finder before drilling - Cost £7.99
- Call an electrician and your insurers. Total cost approx £150. Or use a pipe & mains finder before drilling - Cost £7.99
- Gas pipes shouldn't be buried in walls at the height where you'd mount a bracket, but with a pipe and mains finder for £7.99 it's better to be safe than sorry