Well, yes and no. The primary goal of Speedlock, Alkatraz, and the like, was data protection, rather than copy protection. They used sophisticated multilayered encryption schemes and unusual loaders to prevent other people from looking into the code. Obviously, that was rendered mostly moot by devices such as the Multiface, which dumped the RAM contents after it’d been decrypted. For a casual hacker, however, loading chunks of game code from tape was impossible without reverse-engineering the decryption scheme.
Granted, early versions of Speedlock didn’t use encryption, but modified the standard loading scheme to, say, skip the flag byte, but that quickly changed.
The loaders themselves thus became quite bloated (sometimes they weighed in at 6K or more!), so, perhaps to compensate for that, loading speeds were increased.
Note, that higher loading speeds required a better tape recording setup. While original tapes that came from duplicating plants were almost guaranteed to load on low-end off-the-shelf tape players, their copies (even first-generation copies) were not. That worked as an additional deterrent.
The various tape copiers, which relied on loading game data in chunks into the computer’s RAM and then saving it onto tape—thus creating the highest quality copy—couldn’t deal with most complex protection schemes. Some games used an even simpler trick. They created a standard–speed, non-encrypted but very large single data blocks—over 48K in length. Most of the data there was just junk needed for padding. Since a tape copier would need some room for its own code, it would not be able to load a block that exceeded the size of the remaining free area RAM.
Bleepload’s idea of using the flag byte and loading data in small chunks is hardly a conscious effort to help with loading errors. Each chunk is also encrypted. After each chunk loads, it is decrypted and moved into place.
But yes, some loaders were more forgiving of tape loading errors and user intervention than others. (Some would just reset the machine if they didn’t like something—a terrible user experience decision.) Others—like Bleepload—allowed you to rewind the tape and reload individual blocks.
TL;DR: Fancy loaders were designed to protect IP, rather than to prevent piracy.
