Or at least, I'm pretty sure it was.
Everyone's favorite flop sported a 6502 core in a custom chip package (HuC6280) running at a blistering 7.16Mhz. To put into context, the TG16's biggest competitor, the NES, also used a 6502-compatible CPU but that one ran at 1.79Mhz.
Something really amusing and very much relevant I wish to share here are these screenshots from a YouTube video, the 8-Bit Guy's Commodore History Part 8 video on the Amiga 1000. See here, he compares the 1MHz C64's 6502-compatible CPU to the Amiga's 7Mhz 68000. In this comparison, he shows that clock speed isn't the same as actual computing power and represents that power in MIPS, also by setting both CPUs at the same 1MHz speed to add more clarity.
What he doesn't reveal is going by this comparison, if the 6502 was clocked at 7.16MHz like in the TG16, it would achieve an incredible 3.0788 MIPS. It's no wonder the TG16, by all real definitions an 8-bit computer system, could easily stand toe-to-toe with the 16-bit Sega Genesis. It's also super cool to think this 8-bit console could hand a CD-ROM drive in its later years. The 6502 truly was the ultimate 8-bit powerhouse.
(just all the more doubly sad seeing David 8-Bit Guy - a YouTuber with a massive audience - talking about how amazing the Commander X16 is with its 8MHz 6502, yet continues to ignore the TG16 which was rocking a 7.16MHz 6502 in 1989)